diff --git a/libs/langchain/langchain/chat_models/openai.py b/libs/langchain/langchain/chat_models/openai.py
index 8d1137b6fb..2da3a14d0d 100644
--- a/libs/langchain/langchain/chat_models/openai.py
+++ b/libs/langchain/langchain/chat_models/openai.py
@@ -190,7 +190,7 @@ class ChatOpenAI(BaseChatModel):
     def lc_serializable(self) -> bool:
         return True
 
-    client: Any  #: :meta private:
+    client: Any = None  #: :meta private:
     model_name: str = Field(default="gpt-3.5-turbo", alias="model")
     """Model name to use."""
     temperature: float = 0.7