diff --git a/changes/4458-vetedde.md b/changes/4458-vetedde.md
new file mode 100644
index 0000000000..4b3b1c774e
--- /dev/null
+++ b/changes/4458-vetedde.md
@@ -0,0 +1 @@
+Fix AnyUrl escaping problem by preventing re-quoting an already escaped URL.
diff --git a/pydantic/networks.py b/pydantic/networks.py
index 725e4f8a27..0a6d1735d7 100644
--- a/pydantic/networks.py
+++ b/pydantic/networks.py
@@ -396,6 +396,10 @@ def apply_default_parts(cls, parts: 'Parts') -> 'Parts':
 
     @classmethod
     def quote(cls, string: str, safe: str = '') -> str:
+        pattern = r'^([\w]+|(%\d{2}))+$'
+        if re.match(pattern, string) is not None:
+            return string
+
         return quote_plus(string, safe) if cls.quote_plus else quote(string, safe)
 
     def __repr__(self) -> str:
diff --git a/tests/test_networks.py b/tests/test_networks.py
index 95af277b35..87927115f6 100644
--- a/tests/test_networks.py
+++ b/tests/test_networks.py
@@ -683,6 +683,8 @@ class Model2(BaseModel):
         (dict(scheme='http', user='foo', password='a b', host='example.net'), 'http://foo:a%20b@example.net'),
         (dict(scheme='http', host='example.net', query='q=foo bar'), 'http://example.net?q=foo%20bar'),
         (dict(scheme='http', host='example.net', path="/m&m's"), 'http://example.net/m%26m%27s'),
+        (dict(scheme='http', host='localhost', path='/foo bar'), 'http://localhost/foo%20bar'),
+        (dict(scheme='http', host='localhost', path='/foo%20bar'), 'http://localhost/foo%20bar'),
     ],
 )
 def test_build_url(kwargs, expected):