diff --git a/packages/babel-compat-data/data/plugins.json b/packages/babel-compat-data/data/plugins.json
index 691587999eeb..7c60c3bb5343 100644
--- a/packages/babel-compat-data/data/plugins.json
+++ b/packages/babel-compat-data/data/plugins.json
@@ -2,6 +2,9 @@
   "proposal-class-static-block": {
     "chrome": "91"
   },
+  "proposal-private-property-in-object": {
+    "chrome": "91"
+  },
   "proposal-class-properties": {
     "chrome": "74",
     "opera": "62",
diff --git a/packages/babel-compat-data/scripts/data/plugin-features.js b/packages/babel-compat-data/scripts/data/plugin-features.js
index ca3deb5b2345..49c687f1bf52 100644
--- a/packages/babel-compat-data/scripts/data/plugin-features.js
+++ b/packages/babel-compat-data/scripts/data/plugin-features.js
@@ -136,6 +136,8 @@ const es2021 = {
 
 const shippedProposal = {
   "proposal-class-static-block": "Class static initialization blocks",
+  "proposal-private-property-in-object":
+    "Ergonomic brand checks for private fields",
   "proposal-class-properties": {
     features: [
       "static class fields",
diff --git a/packages/babel-compat-data/scripts/download-compat-table.sh b/packages/babel-compat-data/scripts/download-compat-table.sh
index 53793a1fe9bf..8db31ddeaf3a 100755
--- a/packages/babel-compat-data/scripts/download-compat-table.sh
+++ b/packages/babel-compat-data/scripts/download-compat-table.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-COMPAT_TABLE_COMMIT=ca2d70e305bc3295ade6b06a1c33a929db1ccacf
+COMPAT_TABLE_COMMIT=bcf74805f08ef13371ebe3aa36030bed4cd9a902
 GIT_HEAD=build/compat-table/.git/HEAD
 
 if [ -d "build/compat-table" ]; then
diff --git a/packages/babel-preset-env/data/shipped-proposals.js b/packages/babel-preset-env/data/shipped-proposals.js
index 96f531b55b68..43f92047d48f 100644
--- a/packages/babel-preset-env/data/shipped-proposals.js
+++ b/packages/babel-preset-env/data/shipped-proposals.js
@@ -6,6 +6,7 @@ const proposalPlugins = new Set([
   "proposal-class-properties",
   "proposal-private-methods",
   "proposal-class-static-block",
+  "proposal-private-property-in-object",
 ]);
 
 // use intermediary object to enforce alphabetical key order
@@ -21,6 +22,7 @@ const pluginSyntaxObject = {
   "proposal-optional-chaining": "syntax-optional-chaining",
   // note: we don't have syntax-private-methods
   "proposal-private-methods": "syntax-class-properties",
+  "proposal-private-property-in-object": "syntax-private-property-in-object",
   "proposal-unicode-property-regex": null,
 };
 
diff --git a/packages/babel-preset-env/package.json b/packages/babel-preset-env/package.json
index 8714f22560e0..fce3b84fbe08 100644
--- a/packages/babel-preset-env/package.json
+++ b/packages/babel-preset-env/package.json
@@ -34,6 +34,7 @@
     "@babel/plugin-proposal-optional-catch-binding": "workspace:^7.13.8",
     "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.12",
     "@babel/plugin-proposal-private-methods": "workspace:^7.13.0",
+    "@babel/plugin-proposal-private-property-in-object": "workspace:^7.13.0",
     "@babel/plugin-proposal-unicode-property-regex": "workspace:^7.12.13",
     "@babel/plugin-syntax-async-generators": "^7.8.4",
     "@babel/plugin-syntax-class-properties": "workspace:^7.12.13",
@@ -47,6 +48,7 @@
     "@babel/plugin-syntax-object-rest-spread": "^7.8.3",
     "@babel/plugin-syntax-optional-catch-binding": "^7.8.3",
     "@babel/plugin-syntax-optional-chaining": "^7.8.3",
+    "@babel/plugin-syntax-private-property-in-object": "workspace:^7.13.0",
     "@babel/plugin-syntax-top-level-await": "workspace:^7.12.13",
     "@babel/plugin-transform-arrow-functions": "workspace:^7.13.0",
     "@babel/plugin-transform-async-to-generator": "workspace:^7.13.0",
diff --git a/packages/babel-preset-env/src/available-plugins.js b/packages/babel-preset-env/src/available-plugins.js
index e55cc27debcc..d7fb70a939bb 100644
--- a/packages/babel-preset-env/src/available-plugins.js
+++ b/packages/babel-preset-env/src/available-plugins.js
@@ -13,6 +13,7 @@ import syntaxNumericSeparator from "@babel/plugin-syntax-numeric-separator";
 import syntaxObjectRestSpread from "@babel/plugin-syntax-object-rest-spread";
 import syntaxOptionalCatchBinding from "@babel/plugin-syntax-optional-catch-binding";
 import syntaxOptionalChaining from "@babel/plugin-syntax-optional-chaining";
+import syntaxPrivatePropertyInObject from "@babel/plugin-syntax-private-property-in-object";
 import syntaxTopLevelAwait from "@babel/plugin-syntax-top-level-await";
 import proposalAsyncGeneratorFunctions from "@babel/plugin-proposal-async-generator-functions";
 import proposalClassProperties from "@babel/plugin-proposal-class-properties";
@@ -27,6 +28,7 @@ import proposalObjectRestSpread from "@babel/plugin-proposal-object-rest-spread"
 import proposalOptionalCatchBinding from "@babel/plugin-proposal-optional-catch-binding";
 import proposalOptionalChaining from "@babel/plugin-proposal-optional-chaining";
 import proposalPrivateMethods from "@babel/plugin-proposal-private-methods";
+import proposalPrivatePropertyInObject from "@babel/plugin-proposal-private-property-in-object";
 import proposalUnicodePropertyRegex from "@babel/plugin-proposal-unicode-property-regex";
 import transformAsyncToGenerator from "@babel/plugin-transform-async-to-generator";
 import transformArrowFunctions from "@babel/plugin-transform-arrow-functions";
@@ -93,6 +95,7 @@ export default {
   "proposal-optional-catch-binding": () => proposalOptionalCatchBinding,
   "proposal-optional-chaining": () => proposalOptionalChaining,
   "proposal-private-methods": () => proposalPrivateMethods,
+  "proposal-private-property-in-object": () => proposalPrivatePropertyInObject,
   "proposal-unicode-property-regex": () => proposalUnicodePropertyRegex,
   "syntax-async-generators": () => syntaxAsyncGenerators,
   "syntax-class-properties": () => syntaxClassProperties,
@@ -106,6 +109,7 @@ export default {
   "syntax-object-rest-spread": () => syntaxObjectRestSpread,
   "syntax-optional-catch-binding": () => syntaxOptionalCatchBinding,
   "syntax-optional-chaining": () => syntaxOptionalChaining,
+  "syntax-private-property-in-object": () => syntaxPrivatePropertyInObject,
   "syntax-top-level-await": () => syntaxTopLevelAwait,
   "transform-arrow-functions": () => transformArrowFunctions,
   "transform-async-to-generator": () => transformAsyncToGenerator,
@@ -145,4 +149,5 @@ export default {
 
 export const minVersions = {
   "proposal-class-static-block": "7.12.0",
+  "proposal-private-property-in-object": "7.10.0",
 };
diff --git a/packages/babel-preset-env/src/index.js b/packages/babel-preset-env/src/index.js
index e6c083a03e5b..bb6634b21890 100644
--- a/packages/babel-preset-env/src/index.js
+++ b/packages/babel-preset-env/src/index.js
@@ -394,8 +394,6 @@ option \`forceAllTransforms: true\` instead.
       if (
         pluginName === "proposal-class-properties" ||
         pluginName === "proposal-private-methods" ||
-        // This is not included in preset-env yet, but let's keep it here so we
-        // don't forget about it in the future.
         pluginName === "proposal-private-property-in-object"
       ) {
         return [
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals-chrome-71/stdout.txt
index 3a09cdfdf06a..4af2511633a2 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals/stdout.txt
index d501bfc1feb4..93cec117ed41 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs2-shippedProposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all-chrome-71/stdout.txt
index 77289e9ab95b..958e75dcfbfd 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all/stdout.txt
index 318d328c72cd..349d8cd1c4d8 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-all/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-babel-polyfill/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-babel-polyfill/stdout.txt
index 5dd03a627f41..508a267c46f0 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-babel-polyfill/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-babel-polyfill/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-chrome-71/stdout.txt
index f96c3848b18f..1ac2dde6245e 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals-chrome-71/stdout.txt
index e7ba66cd362f..ffaed0f7f553 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals/stdout.txt
index 1328e0db79c7..2e86cc88d8da 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es-proposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es/stdout.txt
index aed2fa1fab54..1c2f3e34d788 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-es/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only-chrome-71/stdout.txt
index 07769ffcb462..12c006098f55 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only/stdout.txt
index 0cd29b4f92bd..bcaf2b996888 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-runtime-only/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries-chrome-71/stdout.txt
index a6fd6d2963c3..b808eb47fd00 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries/stdout.txt
index ba80ac716ddc..2e1d4a283cae 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-specific-entries/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-chrome-71/stdout.txt
index 21fc079d1b03..7a35910e8fd1 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-samsung-8.2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-samsung-8.2/stdout.txt
index f8314e71a34d..c2193ff7def2 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-samsung-8.2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable-samsung-8.2/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { samsung }
+  proposal-private-property-in-object { samsung }
   proposal-class-properties { samsung }
   proposal-private-methods { samsung }
   proposal-numeric-separator { samsung < 11 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable/stdout.txt
index 57fed1f3eec8..2bf51a3dbe87 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stable/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage-chrome-71/stdout.txt
index 2875f456852a..31bd6fb4df92 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage/stdout.txt
index 5bc6800eaa49..27480b80a336 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-stage/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web-chrome-71/stdout.txt
index 6075ed91436c..72085bb03229 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web/stdout.txt
index a20e766fc632..53617e7ff8ad 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-corejs3-web/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-no-corejs-shippedProposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-no-corejs-shippedProposals/stdout.txt
index 05b0129fa696..9a5f98e41c8f 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-no-corejs-shippedProposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/entry-no-corejs-shippedProposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-80/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-80/stdout.txt
index d4d9db78cf16..9c8b3e4a4534 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-80/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-80/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   syntax-numeric-separator
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-84/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-84/stdout.txt
index dcdf235ab581..d5ac3a7cb181 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-84/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/shippedProposals-chrome-84/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   syntax-class-properties
   syntax-numeric-separator
   proposal-logical-assignment-operators { chrome < 85 }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-1/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-1/stdout.txt
index 4b1e5d5190da..18944ea30ea1 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-1/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-1/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-2/stdout.txt
index f8c122d3110a..f151202e1031 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs2-shippedProposals-2/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-1/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-1/stdout.txt
index 6382df362efd..b8f57b58b775 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-1/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-1/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-2/stdout.txt
index 392519960df5..3fdc2a1bda75 100644
--- a/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug-babel-7/usage-corejs3-shippedProposals-2/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals-chrome-71/stdout.txt
index b1a3ffb9057e..e928f6277d2b 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals/stdout.txt
index 99be3a5df38e..e36a14f07740 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs2-shippedProposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all-chrome-71/stdout.txt
index d1b82e2ad6df..6fffa4b913b4 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all/stdout.txt
index 7901694de254..bce49b559a28 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-all/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-babel-polyfill/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-babel-polyfill/stdout.txt
index 18dd722656c3..ee6b4d9fb6a5 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-babel-polyfill/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-babel-polyfill/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-chrome-71/stdout.txt
index a2ceded6251c..0220f1907085 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals-chrome-71/stdout.txt
index 5bdede8137a3..71c74afd46ab 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals/stdout.txt
index 03ef9fd230a5..461c3cfc71b1 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es-proposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es/stdout.txt
index 0b482ee835d1..b63af9d26cf1 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-es/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only-chrome-71/stdout.txt
index db8e43d642e9..4f2ac405ec43 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only/stdout.txt
index 50a939baec4a..bb650165a20c 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-runtime-only/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries-chrome-71/stdout.txt
index 42f6b7b4cca7..bbf63c9685fb 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries/stdout.txt
index d167c4dc2408..9e727e8b28bf 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-specific-entries/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-chrome-71/stdout.txt
index 900f91a824e4..56ab137952d0 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-samsung-8.2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-samsung-8.2/stdout.txt
index 95c730254e59..bbe014d7f9ef 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-samsung-8.2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable-samsung-8.2/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { samsung }
+  proposal-private-property-in-object { samsung }
   proposal-class-properties { samsung }
   proposal-private-methods { samsung }
   proposal-numeric-separator { samsung < 11 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable/stdout.txt
index cbc58e06d152..bfcbcddf7e49 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stable/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage-chrome-71/stdout.txt
index 87fab870f1a0..4741dd6a3a56 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage/stdout.txt
index 1daa69cfc3aa..7cea354bda47 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-stage/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web-chrome-71/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web-chrome-71/stdout.txt
index bed42c549da2..57c4755987fd 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web-chrome-71/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web-chrome-71/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   proposal-numeric-separator { chrome < 75 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web/stdout.txt
index a2c948e73ce5..96aaa680a7cc 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-corejs3-web/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stdout.txt
index 6bd31f22f5ca..2684419386f1 100644
--- a/packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/entry-no-corejs-shippedProposals/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { ie }
+  proposal-private-property-in-object { ie }
   proposal-class-properties { ie }
   proposal-private-methods { ie }
   proposal-numeric-separator { ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-80/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-80/stdout.txt
index d4d9db78cf16..9c8b3e4a4534 100644
--- a/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-80/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-80/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   proposal-class-properties { chrome < 84 }
   proposal-private-methods { chrome < 84 }
   syntax-numeric-separator
diff --git a/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-84/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-84/stdout.txt
index dcdf235ab581..d5ac3a7cb181 100644
--- a/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-84/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/shippedProposals-chrome-84/stdout.txt
@@ -9,6 +9,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91 }
+  proposal-private-property-in-object { chrome < 91 }
   syntax-class-properties
   syntax-numeric-separator
   proposal-logical-assignment-operators { chrome < 85 }
diff --git a/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-1/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-1/stdout.txt
index 5776ff9d0bd1..62a6693710f5 100644
--- a/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-1/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-1/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-2/stdout.txt
index 03be5fbb6f67..953b73860fd1 100644
--- a/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-shippedProposals-2/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-1/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-1/stdout.txt
index 7521b8ae98d9..0c84d12875c9 100644
--- a/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-1/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-1/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-2/stdout.txt b/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-2/stdout.txt
index d2290f9e64f5..49f039b85375 100644
--- a/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-2/stdout.txt
+++ b/packages/babel-preset-env/test/fixtures/debug/usage-corejs3-shippedProposals-2/stdout.txt
@@ -11,6 +11,7 @@ Using modules transform: auto
 
 Using plugins:
   proposal-class-static-block { chrome < 91, firefox, ie }
+  proposal-private-property-in-object { chrome < 91, firefox, ie }
   proposal-class-properties { chrome < 84, firefox, ie }
   proposal-private-methods { chrome < 84, firefox, ie }
   proposal-numeric-separator { chrome < 75, firefox < 70, ie }
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/stderr.txt b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/stderr.txt
index 90fafc7e535b..637316b477db 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/stderr.txt
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/methods-loose-preset-not-loose/stderr.txt
@@ -1,4 +1,8 @@
-Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-class-properties since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-class-properties since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-class-properties", { "loose": true }]
 to the "plugins" section of your Babel config.
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/stderr.txt b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/stderr.txt
new file mode 100644
index 000000000000..1e9c2f53b2cc
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-loose-preset-not-loose/stderr.txt
@@ -0,0 +1,4 @@
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/stderr.txt b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/stderr.txt
new file mode 100644
index 000000000000..1022c38841fd
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-and-methods-not-loose-preset-loose/stderr.txt
@@ -0,0 +1,4 @@
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "false" for @babel/plugin-proposal-private-methods.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": false }]
+to the "plugins" section of your Babel config.
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/stderr.txt b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/stderr.txt
index 68b6ffd194ce..4e1891bf445c 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/stderr.txt
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-loose-preset-not-loose/stderr.txt
@@ -1,4 +1,8 @@
-Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "true" for @babel/plugin-proposal-class-properties.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-class-properties.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": true }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "true" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-private-methods", { "loose": true }]
 to the "plugins" section of your Babel config.
diff --git a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/stderr.txt b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/stderr.txt
index 69f2a4eda409..c7b671d4ee7b 100644
--- a/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/stderr.txt
+++ b/packages/babel-preset-env/test/fixtures/loose-class-features-precedence/properties-not-loose-preset-loose/stderr.txt
@@ -1,4 +1,8 @@
-Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "false" for @babel/plugin-proposal-class-properties.
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-private-property-in-object since the "loose" mode option was set to "false" for @babel/plugin-proposal-class-properties.
+The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
+	["@babel/plugin-proposal-private-private-property-in-object", { "loose": false }]
+to the "plugins" section of your Babel config.
+Though the "loose" option was set to "true" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-methods since the "loose" mode option was set to "false" for @babel/plugin-proposal-private-private-property-in-object.
 The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding
 	["@babel/plugin-proposal-private-methods", { "loose": false }]
 to the "plugins" section of your Babel config.
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/input.js
deleted file mode 100644
index 11f7d7c96d79..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/input.js
+++ /dev/null
@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/output.js
deleted file mode 100644
index 53afe864cd8f..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/output.js
+++ /dev/null
@@ -1,5 +0,0 @@
-class A {
-  static #_ = (() => {
-    register(A);
-  })();
-}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/input.js
deleted file mode 100644
index 11f7d7c96d79..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/input.js
+++ /dev/null
@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/output.js
deleted file mode 100644
index 11f7d7c96d79..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/output.js
+++ /dev/null
@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/input.js
deleted file mode 100644
index 11f7d7c96d79..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/input.js
+++ /dev/null
@@ -1,5 +0,0 @@
-class A {
-  static {
-    register(A);
-  }
-}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/output.js
deleted file mode 100644
index 6e4f4f2bcc2f..000000000000
--- a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/output.js
+++ /dev/null
@@ -1,8 +0,0 @@
-class A {}
-
-var _ = {
-  writable: true,
-  value: (() => {
-    register(A);
-  })()
-};
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/input.js
new file mode 100644
index 000000000000..d5bcaa342150
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/input.js
@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/options.json b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/options.json
similarity index 100%
rename from packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-90/options.json
rename to packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/options.json
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js
new file mode 100644
index 000000000000..ce3182dcfd26
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-90/output.js
@@ -0,0 +1,8 @@
+var _fooBrandCheck = new WeakSet();
+
+class A {
+  #foo = void _fooBrandCheck.add(this);
+  static #_ = (() => {
+    register(A, _fooBrandCheck.has(A));
+  })();
+}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/input.js
new file mode 100644
index 000000000000..d5bcaa342150
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/input.js
@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/options.json b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/options.json
similarity index 100%
rename from packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-chrome-91/options.json
rename to packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/options.json
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/output.js
new file mode 100644
index 000000000000..49dd03d43a35
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-chrome-91/output.js
@@ -0,0 +1,6 @@
+class A {
+  #foo;
+  static {
+    register(A, #foo in A);
+  }
+}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/input.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/input.js
new file mode 100644
index 000000000000..d5bcaa342150
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/input.js
@@ -0,0 +1,7 @@
+class A {
+  #foo;
+
+  static {
+    register(A, #foo in A);
+  }
+}
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/options.json b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/options.json
similarity index 100%
rename from packages/babel-preset-env/test/fixtures/shipped-proposals/class-static-block-firefox-70/options.json
rename to packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/options.json
diff --git a/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js
new file mode 100644
index 000000000000..c953ed142041
--- /dev/null
+++ b/packages/babel-preset-env/test/fixtures/shipped-proposals/new-class-features-firefox-70/output.js
@@ -0,0 +1,18 @@
+var _foo = new WeakMap();
+
+class A {
+  constructor() {
+    _foo.set(this, {
+      writable: true,
+      value: void 0
+    });
+  }
+
+}
+
+var _ = {
+  writable: true,
+  value: (() => {
+    register(A, _foo.has(A));
+  })()
+};
diff --git a/yarn.lock b/yarn.lock
index 93427ff20f32..61713bf165a9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1434,7 +1434,7 @@ __metadata:
   languageName: unknown
   linkType: soft
 
-"@babel/plugin-proposal-private-property-in-object@workspace:*, @babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object":
+"@babel/plugin-proposal-private-property-in-object@workspace:*, @babel/plugin-proposal-private-property-in-object@workspace:^7.13.0, @babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object":
   version: 0.0.0-use.local
   resolution: "@babel/plugin-proposal-private-property-in-object@workspace:packages/babel-plugin-proposal-private-property-in-object"
   dependencies:
@@ -3099,6 +3099,7 @@ __metadata:
     "@babel/plugin-proposal-optional-catch-binding": "workspace:^7.13.8"
     "@babel/plugin-proposal-optional-chaining": "workspace:^7.13.12"
     "@babel/plugin-proposal-private-methods": "workspace:^7.13.0"
+    "@babel/plugin-proposal-private-property-in-object": "workspace:^7.13.0"
     "@babel/plugin-proposal-unicode-property-regex": "workspace:^7.12.13"
     "@babel/plugin-syntax-async-generators": ^7.8.4
     "@babel/plugin-syntax-class-properties": "workspace:^7.12.13"
@@ -3112,6 +3113,7 @@ __metadata:
     "@babel/plugin-syntax-object-rest-spread": ^7.8.3
     "@babel/plugin-syntax-optional-catch-binding": ^7.8.3
     "@babel/plugin-syntax-optional-chaining": ^7.8.3
+    "@babel/plugin-syntax-private-property-in-object": "workspace:^7.13.0"
     "@babel/plugin-syntax-top-level-await": "workspace:^7.12.13"
     "@babel/plugin-transform-arrow-functions": "workspace:^7.13.0"
     "@babel/plugin-transform-async-to-generator": "workspace:^7.13.0"