diff --git a/autogen/oai/gemini.py b/autogen/oai/gemini.py
index 02fa5df54f..1ac13c2718 100644
--- a/autogen/oai/gemini.py
+++ b/autogen/oai/gemini.py
@@ -272,7 +272,7 @@ def create(self, params: dict) -> ChatCompletion:
                 if fn_call not in prev_function_calls:
                     autogen_tool_calls.append(
                         ChatCompletionMessageToolCall(
-                            id=random_id,
+                            id=str(random_id),
                             function={
                                 "name": fn_call.name,
                                 "arguments": (