diff --git a/python/google/protobuf/descriptor_pool.py b/python/google/protobuf/descriptor_pool.py
index 733c9a6ac8dd..aa90cce0d12d 100644
--- a/python/google/protobuf/descriptor_pool.py
+++ b/python/google/protobuf/descriptor_pool.py
@@ -805,12 +805,17 @@ def _ConvertFileProtoToFileDescriptor(self, file_proto):
       self._file_descriptors[file_proto.name] = file_descriptor
 
     # Add extensions to the pool
+    def AddExtensionForNested(message_type):
+      for nested in message_type.nested_types:
+        AddExtensionForNested(nested)
+      for extension in message_type.extensions:
+        self._AddExtensionDescriptor(extension)
+
     file_desc = self._file_descriptors[file_proto.name]
     for extension in file_desc.extensions_by_name.values():
       self._AddExtensionDescriptor(extension)
     for message_type in file_desc.message_types_by_name.values():
-      for extension in message_type.extensions:
-        self._AddExtensionDescriptor(extension)
+      AddExtensionForNested(message_type)
 
     return file_desc
 
diff --git a/python/google/protobuf/internal/builder.py b/python/google/protobuf/internal/builder.py
index 64353ee4af60..5beb21678363 100644
--- a/python/google/protobuf/internal/builder.py
+++ b/python/google/protobuf/internal/builder.py
@@ -38,6 +38,7 @@
 __author__ = 'jieluo@google.com (Jie Luo)'
 
 from google.protobuf.internal import enum_type_wrapper
+from google.protobuf.internal import python_message
 from google.protobuf import message as _message
 from google.protobuf import reflection as _reflection
 from google.protobuf import symbol_database as _symbol_database
@@ -108,6 +109,28 @@ def BuildMessage(msg_des):
     module[name] = BuildMessage(msg_des)
 
 
+def AddHelpersToExtensions(file_des):
+  """Adds field helpers to extensions.
+
+  Args:
+    file_des: FileDescriptor of the .proto file
+  """
+  def AddHelpersToExtension(extension):
+    python_message._AttachFieldHelpers(
+        extension.containing_type._concrete_class, extension)
+
+  def AddHelpersToNestedExtensions(msg_des):
+    for nested_type in msg_des.nested_types:
+      AddHelpersToNestedExtensions(nested_type)
+    for extension in msg_des.extensions:
+      AddHelpersToExtension(extension)
+
+  for extension in file_des.extensions_by_name.values():
+    AddHelpersToExtension(extension)
+  for message_type in file_des.message_types_by_name.values():
+    AddHelpersToNestedExtensions(message_type)
+
+
 def BuildServices(file_des, module_name, module):
   """Builds services classes and services stub class.
 
diff --git a/src/google/protobuf/compiler/python/generator.cc b/src/google/protobuf/compiler/python/generator.cc
index 636808a3ae20..fc63c34d6b5b 100644
--- a/src/google/protobuf/compiler/python/generator.cc
+++ b/src/google/protobuf/compiler/python/generator.cc
@@ -331,10 +331,11 @@ bool Generator::Generate(const FileDescriptor* file,
   printer.Print("if _descriptor._USE_C_DESCRIPTORS == False:\n");
   printer_->Indent();
 
-  // We have to fix up the extensions after the message classes themselves,
-  // since they need to call static RegisterExtension() methods on these
-  // classes.
-  FixForeignFieldsInExtensions();
+  // We have to fix up the extensions after the message classes themselves
+  if (HasExtensions()) {
+    printer.Print("_builder.AddHelpersToExtensions(DESCRIPTOR)\n");
+  }
+
   // Descriptor options may have custom extensions. These custom options
   // can only be successfully parsed after we register corresponding
   // extensions. Therefore we parse all options again here to recognize
@@ -1006,47 +1007,20 @@ void Generator::FixForeignFieldsInDescriptors() const {
   printer_->Print("\n");
 }
 
-// We need to not only set any necessary message_type fields, but
-// also need to call RegisterExtension() on each message we're
-// extending.
-void Generator::FixForeignFieldsInExtensions() const {
-  // Top-level extensions.
-  for (int i = 0; i < file_->extension_count(); ++i) {
-    FixForeignFieldsInExtension(*file_->extension(i));
-  }
-  // Nested extensions.
+bool Generator::HasExtensions() const {
+  if (file_->extension_count() > 0) return true;
   for (int i = 0; i < file_->message_type_count(); ++i) {
-    FixForeignFieldsInNestedExtensions(*file_->message_type(i));
+    if (HasExtensionsInMessage(*file_->message_type(i))) return true;
   }
-  printer_->Print("\n");
-}
-
-void Generator::FixForeignFieldsInExtension(
-    const FieldDescriptor& extension_field) const {
-  ABSL_CHECK(extension_field.is_extension());
-
-  absl::flat_hash_map<absl::string_view, std::string> m;
-  // Confusingly, for FieldDescriptors that happen to be extensions,
-  // containing_type() means "extended type."
-  // On the other hand, extension_scope() will give us what we normally
-  // mean by containing_type().
-  m["extended_message_class"] =
-      ModuleLevelMessageName(*extension_field.containing_type());
-  m["field"] = FieldReferencingExpression(
-      extension_field.extension_scope(), extension_field, "extensions_by_name");
-  printer_->Print(m, "$extended_message_class$.RegisterExtension($field$)\n");
+  return false;
 }
 
-void Generator::FixForeignFieldsInNestedExtensions(
-    const Descriptor& descriptor) const {
-  // Recursively fix up extensions in all nested types.
+bool Generator::HasExtensionsInMessage(const Descriptor& descriptor) const {
+  if (descriptor.extension_count() > 0) return true;
   for (int i = 0; i < descriptor.nested_type_count(); ++i) {
-    FixForeignFieldsInNestedExtensions(*descriptor.nested_type(i));
-  }
-  // Fix up extensions directly contained within this type.
-  for (int i = 0; i < descriptor.extension_count(); ++i) {
-    FixForeignFieldsInExtension(*descriptor.extension(i));
+    if (HasExtensionsInMessage(*descriptor.nested_type(i))) return true;
   }
+  return false;
 }
 
 // Returns a Python expression that instantiates a Python EnumValueDescriptor
diff --git a/src/google/protobuf/compiler/python/generator.h b/src/google/protobuf/compiler/python/generator.h
index 65c16f591eb0..99537f1e3be6 100644
--- a/src/google/protobuf/compiler/python/generator.h
+++ b/src/google/protobuf/compiler/python/generator.h
@@ -141,10 +141,8 @@ class PROTOC_EXPORT Generator : public CodeGenerator {
       const DescriptorT& descriptor,
       const Descriptor* containing_descriptor) const;
 
-  void FixForeignFieldsInExtensions() const;
-  void FixForeignFieldsInExtension(
-      const FieldDescriptor& extension_field) const;
-  void FixForeignFieldsInNestedExtensions(const Descriptor& descriptor) const;
+  bool HasExtensions() const;
+  bool HasExtensionsInMessage(const Descriptor& descriptor) const;
 
   void PrintTopBoilerplate() const;
   void PrintServices() const;