diff --git a/src/pipecat/services/tts_service.py b/src/pipecat/services/tts_service.py
index f0d602a405..392c1e83f0 100644
--- a/src/pipecat/services/tts_service.py
+++ b/src/pipecat/services/tts_service.py
@@ -364,7 +364,10 @@ async def process_frame(self, frame: Frame, direction: FrameDirection):
                 sentence, includes_inter_frame_spaces=includes_inter_frame_spaces
             )
             if isinstance(frame, LLMFullResponseEndFrame):
-                if self._push_text_frames:
+                # Ensure the sentence is not empty. In some cases, such as function calling, the
+                # LLMFullResponseEndFrame may never be pushed into the pipeline, which would
+                # cause issues if we proceed without "or not sentence" this check.
+                if self._push_text_frames or not sentence:
                     await self.push_frame(frame, direction)
             else:
                 await self.push_frame(frame, direction)