diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
index 6484358d8a..cdcd3ddf87 100644
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -5,7 +5,8 @@ final class PhabricatorCalendarEvent extends PhabricatorCalendarDAO
   PhabricatorMarkupInterface,
   PhabricatorApplicationTransactionInterface,
   PhabricatorSubscribableInterface,
-  PhabricatorTokenReceiverInterface {
+  PhabricatorTokenReceiverInterface,
+  PhabricatorMentionableInterface {
 
   protected $name;
   protected $userPHID;