diff --git a/.github/trigger_files/beam_PostCommit_Python.json b/.github/trigger_files/beam_PostCommit_Python.json
index 815b511b8988..42a6e88b8a29 100644
--- a/.github/trigger_files/beam_PostCommit_Python.json
+++ b/.github/trigger_files/beam_PostCommit_Python.json
@@ -1,5 +1,5 @@
 {
   "comment": "Modify this file in a trivial way to cause this test suite to run.",
-  "modification": 30
+  "modification": 31
 }
 
diff --git a/sdks/python/apache_beam/transforms/core.py b/sdks/python/apache_beam/transforms/core.py
index db4a652cf97e..23399ef79106 100644
--- a/sdks/python/apache_beam/transforms/core.py
+++ b/sdks/python/apache_beam/transforms/core.py
@@ -3054,6 +3054,10 @@ def _process_argspec_fn(self):
     return lambda element, *args, **kwargs: None
 
   def expand(self, pcoll):
+    # When using gbek, don't allow overriding default implementation
+    gbek_option = (pcoll.pipeline._options.view_as(SetupOptions).gbek)
+    self._using_gbek = (gbek_option is not None and len(gbek_option) > 0)
+
     args, kwargs = util.insert_values_in_args(
         self.args, self.kwargs, self.side_inputs)
     return pcoll | GroupByKey() | 'Combine' >> CombineValues(
@@ -3079,7 +3083,9 @@ def to_runner_api_parameter(
       self,
       context,  # type: PipelineContext
   ):
-    # type: (...) -> typing.Tuple[str, beam_runner_api_pb2.CombinePayload]
+    # type: (...) -> tuple[str, typing.Optional[typing.Union[message.Message, bytes, str]]]
+    if getattr(self, '_using_gbek', False):
+      return super().to_runner_api_parameter(context)
     if self.args or self.kwargs:
       from apache_beam.transforms.combiners import curry_combine_fn
       combine_fn = curry_combine_fn(self.fn, self.args, self.kwargs)
diff --git a/sdks/python/apache_beam/transforms/core_it_test.py b/sdks/python/apache_beam/transforms/core_it_test.py
new file mode 100644
index 000000000000..50744e28c674
--- /dev/null
+++ b/sdks/python/apache_beam/transforms/core_it_test.py
@@ -0,0 +1,109 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Integration tests for cross-language transform expansion."""
+
+# pytype: skip-file
+
+import random
+import string
+import unittest
+
+import pytest
+
+import apache_beam as beam
+from apache_beam.options.pipeline_options import SetupOptions
+from apache_beam.testing.test_pipeline import TestPipeline
+from apache_beam.testing.util import assert_that
+from apache_beam.testing.util import equal_to
+from apache_beam.transforms.util import GcpSecret
+from apache_beam.transforms.util import Secret
+
+try:
+  from google.cloud import secretmanager
+except ImportError:
+  secretmanager = None  # type: ignore[assignment]
+
+
+class GbekIT(unittest.TestCase):
+  def setUp(self):
+    if secretmanager is not None:
+      self.project_id = 'apache-beam-testing'
+      secret_postfix = ''.join(random.choice(string.digits) for _ in range(6))
+      self.secret_id = 'gbek_secret_tests_' + secret_postfix
+      self.client = secretmanager.SecretManagerServiceClient()
+      self.project_path = f'projects/{self.project_id}'
+      self.secret_path = f'{self.project_path}/secrets/{self.secret_id}'
+      try:
+        self.client.get_secret(request={'name': self.secret_path})
+      except Exception:
+        self.client.create_secret(
+            request={
+                'parent': self.project_path,
+                'secret_id': self.secret_id,
+                'secret': {
+                    'replication': {
+                        'automatic': {}
+                    }
+                }
+            })
+        self.client.add_secret_version(
+            request={
+                'parent': self.secret_path,
+                'payload': {
+                    'data': Secret.generate_secret_bytes()
+                }
+            })
+      version_name = f'{self.secret_path}/versions/latest'
+      self.gcp_secret = GcpSecret(version_name)
+      self.secret_option = f'type:GcpSecret;version_name:{version_name}'
+
+  def tearDown(self):
+    if secretmanager is not None:
+      self.client.delete_secret(request={'name': self.secret_path})
+
+  @pytest.mark.it_postcommit
+  @unittest.skipIf(secretmanager is None, 'GCP dependencies are not installed')
+  def test_gbk_with_gbek_it(self):
+    pipeline = TestPipeline(is_integration_test=True)
+    pipeline.options.view_as(SetupOptions).gbek = self.secret_option
+
+    pcoll_1 = pipeline | 'Start 1' >> beam.Create([('a', 1), ('a', 2), ('b', 3),
+                                                   ('c', 4)])
+    result = (pcoll_1) | beam.GroupByKey()
+    sorted_result = result | beam.Map(lambda x: (x[0], sorted(x[1])))
+    assert_that(
+        sorted_result, equal_to([('a', ([1, 2])), ('b', ([3])), ('c', ([4]))]))
+
+    pipeline.run().wait_until_finish()
+
+  @pytest.mark.it_postcommit
+  @unittest.skipIf(secretmanager is None, 'GCP dependencies are not installed')
+  def test_combineValues_with_gbek_it(self):
+    pipeline = TestPipeline(is_integration_test=True)
+    pipeline.options.view_as(SetupOptions).gbek = self.secret_option
+
+    pcoll_1 = pipeline | 'Start 1' >> beam.Create([('a', 1), ('a', 2), ('b', 3),
+                                                   ('c', 4)])
+    result = (pcoll_1) | beam.CombinePerKey(sum)
+    assert_that(result, equal_to([('a', 3), ('b', 3), ('c', 4)]))
+
+    pipeline.run().wait_until_finish()
+
+
+if __name__ == '__main__':
+  unittest.main()