diff --git a/litellm/tests/test_completion.py b/litellm/tests/test_completion.py
index afdc598b44..31ac792d8e 100644
--- a/litellm/tests/test_completion.py
+++ b/litellm/tests/test_completion.py
@@ -1436,6 +1436,43 @@ def test_hf_test_completion_tgi():
 
 # hf_test_completion_tgi()
 
+
+@pytest.mark.parametrize("provider", ["vertex_ai_beta"])  # "vertex_ai",
+@pytest.mark.asyncio
+async def test_openai_compatible_custom_api_base(provider):
+    litellm.set_verbose = True
+    messages = [
+        {
+            "role": "user",
+            "content": "Hello world",
+        }
+    ]
+    from openai import OpenAI
+
+    openai_client = OpenAI(api_key="fake-key")
+
+    with patch.object(
+        openai_client.chat.completions, "create", new=MagicMock()
+    ) as mock_call:
+        try:
+            response = completion(
+                model="openai/my-vllm-model",
+                messages=messages,
+                response_format={"type": "json_object"},
+                client=openai_client,
+                api_base="my-custom-api-base",
+                hello="world",
+            )
+        except Exception as e:
+            pass
+
+        mock_call.assert_called_once()
+
+        print("Call KWARGS - {}".format(mock_call.call_args.kwargs))
+
+        assert "hello" in mock_call.call_args.kwargs["extra_body"]
+
+
 # ################### Hugging Face Conversational models ########################
 # def hf_test_completion_conv():
 #     try:
diff --git a/litellm/tests/test_text_completion.py b/litellm/tests/test_text_completion.py
index 32c969ac72..c6bbf71f22 100644
--- a/litellm/tests/test_text_completion.py
+++ b/litellm/tests/test_text_completion.py
@@ -4189,12 +4189,12 @@ def test_completion_vllm():
 
     with patch.object(client.completions, "create", side_effect=mock_post) as mock_call:
         response = text_completion(
-            model="openai/gemini-1.5-flash",
-            prompt="ping",
-            client=client,
+            model="openai/gemini-1.5-flash", prompt="ping", client=client, hello="world"
         )
         print(response)
 
         assert response.usage.prompt_tokens == 2
 
         mock_call.assert_called_once()
+
+        assert "hello" in mock_call.call_args.kwargs["extra_body"]
diff --git a/litellm/utils.py b/litellm/utils.py
index 02b7bfd48f..eb62204f55 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -3265,7 +3265,11 @@ def get_optional_params(
             optional_params["top_logprobs"] = top_logprobs
         if extra_headers is not None:
             optional_params["extra_headers"] = extra_headers
-    if custom_llm_provider in ["openai", "azure"] + litellm.openai_compatible_providers:
+    if (
+        custom_llm_provider
+        in ["openai", "azure", "text-completion-openai"]
+        + litellm.openai_compatible_providers
+    ):
         # for openai, azure we should pass the extra/passed params within `extra_body` https://github.com/openai/openai-python/blob/ac33853ba10d13ac149b1fa3ca6dba7d613065c9/src/openai/resources/models.py#L46
         extra_body = passed_params.pop("extra_body", {})
         for k in passed_params.keys():