diff --git a/lib/plugins/aws/provider.js b/lib/plugins/aws/provider.js
index 91644a56ffa..424455edd04 100644
--- a/lib/plugins/aws/provider.js
+++ b/lib/plugins/aws/provider.js
@@ -480,6 +480,16 @@ class AwsProvider {
             required: ['Fn::Sub'],
             additionalProperties: false,
           },
+          awsCfToJsonString: {
+            type: 'object',
+            properties: {
+              'Fn::ToJsonString': {
+                anyOf: [{ type: 'object' }, { type: 'array' }],
+              },
+            },
+            required: ['Fn::ToJsonString'],
+            additionalProperties: false,
+          },
           awsIamPolicyAction: { type: 'array', items: { type: 'string' } },
           awsIamPolicyPrincipal: {
             anyOf: [
@@ -567,6 +577,7 @@ class AwsProvider {
                   { $ref: '#/definitions/awsCfInstruction' },
                   { $ref: '#/definitions/awsCfIf' },
                   { $ref: '#/definitions/awsCfSelect' },
+                  { $ref: '#/definitions/awsCfToJsonString' },
                 ],
               },
             },