diff --git a/icekit_events/apps.py b/icekit_events/apps.py
index e900bde..af04a0c 100644
--- a/icekit_events/apps.py
+++ b/icekit_events/apps.py
@@ -23,5 +23,5 @@ def ready(self):
         autodiscover_modules('event_type_plugins')
 
         from .models import EventBase
-        ICEkitURLField.register_model(
+        ICEkitURLField.register_model_once(
             EventBase, widget=SimpleRawIdWidget(EventBase), title='Event')