diff --git a/src/pipecat/services/elevenlabs/tts.py b/src/pipecat/services/elevenlabs/tts.py
index 324e8099e..1b78db904 100644
--- a/src/pipecat/services/elevenlabs/tts.py
+++ b/src/pipecat/services/elevenlabs/tts.py
@@ -425,7 +425,7 @@ class ElevenLabsTTSService(AudioContextWordTTSService):
         if self._websocket:
             if not self._context_id:
                 # First message for a new context - need a space to initialize
-                msg = {"text": " ", "context_id": str(uuid.uuid4()), "xi_api_key": self._api_key}
+                msg = {"text": " ", "context_id": str(uuid.uuid4()), "xi-api-key": self._api_key}
 
                 # Add voice settings only in first message for a context
                 if self._voice_settings: