diff --git a/langchain/retrievers/time_weighted_retriever.py b/langchain/retrievers/time_weighted_retriever.py
index f715337b0a9..b46325f4ca0 100644
--- a/langchain/retrievers/time_weighted_retriever.py
+++ b/langchain/retrievers/time_weighted_retriever.py
@@ -127,7 +127,9 @@ class TimeWeightedVectorStoreRetriever(BaseRetriever, BaseModel):
         self, documents: List[Document], **kwargs: Any
     ) -> List[str]:
         """Add documents to vectorstore."""
-        current_time = kwargs.get("current_time", datetime.datetime.now())
+        current_time = kwargs.get("current_time")
+        if current_time is None:
+            current_time = datetime.datetime.now()
         # Avoid mutating input documents
         dup_docs = [deepcopy(d) for d in documents]
         for i, doc in enumerate(dup_docs):