diff --git a/program/views.py b/program/views.py
index 90d61987de3f1e267cc96eb0782cf7c0d11d1f6c..8e88c6efe90caf5a095a538de925d3a9685acdea 100644
--- a/program/views.py
+++ b/program/views.py
@@ -100,7 +100,8 @@ def timeslot_entry(*, timeslot: TimeSlot) -> dict:
         "end": timeslot.end.strftime("%Y-%m-%dT%H:%M:%S"),
         "title": title,
         "schedule_id": schedule.id,
-        "is_repetition": timeslot.is_repetition,
+        # `Timeslot.repetition_of` is a foreign key that can be null
+        "is_repetition": timeslot.repetition_of.id if timeslot.repetition_of else False,
         "playlist_id": playlist_id,
         "schedule_default_playlist_id": schedule.default_playlist_id,
         "show_default_playlist_id": show.default_playlist_id,