diff --git a/python/packages/autogen-ext/src/autogen_ext/models/openai/config/__init__.py b/python/packages/autogen-ext/src/autogen_ext/models/openai/config/__init__.py
index a6b484780212..de27637c4663 100644
--- a/python/packages/autogen-ext/src/autogen_ext/models/openai/config/__init__.py
+++ b/python/packages/autogen-ext/src/autogen_ext/models/openai/config/__init__.py
@@ -74,7 +74,7 @@ class BaseOpenAIClientConfigurationConfigModel(CreateArgumentsConfigModel):
     max_retries: int | None = None
     model_capabilities: ModelCapabilities | None = None  # type: ignore
     model_info: ModelInfo | None = None
-
+    default_header: Dict[str, str] | None = None
 
 # See OpenAI docs for explanation of these parameters
 class OpenAIClientConfigurationConfigModel(BaseOpenAIClientConfigurationConfigModel):
diff --git a/python/packages/autogen-ext/src/autogen_ext/models/test.py b/python/packages/autogen-ext/src/autogen_ext/models/test.py
new file mode 100644
index 000000000000..c926e5925b7d
--- /dev/null
+++ b/python/packages/autogen-ext/src/autogen_ext/models/test.py
@@ -0,0 +1,10 @@
+from src.autogen_ext.models.openai import AzureOpenAIChatCompletionClient
+
+model_client = AzureOpenAIChatCompletionClient(
+    model="gpt-4o-2024-05-13",
+    azure_deployment="xxxxxx",
+    azure_endpoint="xxxxxx",
+    api_version="xxxx",
+    api_key=os.getenv("AZURE_API_KEY"),
+    default_headers={"X-User-Id": os.getlogin()},
+)