diff --git a/clay/core/gp/track.py b/clay/core/gp/track.py
index 15a4222..9e0f98d 100644
--- a/clay/core/gp/track.py
+++ b/clay/core/gp/track.py
@@ -173,7 +173,7 @@ def on_get_url(url, error):
         if client.gp.is_subscribed:
             track_id = self.store_id
         else:
-            track_id = self.library_id
+            track_id = str(self.library_id)
         client.gp.get_stream_url_async(track_id, callback=on_get_url)
 
     @synchronized