diff --git a/library/includes/ucp/topic_watch.php b/library/includes/ucp/topic_watch.php
index 4ce7e0aa1..679b161e3 100644
--- a/library/includes/ucp/topic_watch.php
+++ b/library/includes/ucp/topic_watch.php
@@ -7,6 +7,10 @@
  * @license   https://github.com/torrentpier/torrentpier/blob/master/LICENSE MIT License
  */
 
+if (!defined('BB_ROOT')) {
+    die(basename(__FILE__));
+}
+
 if (!$bb_cfg['topic_notify_enabled']) {
     bb_die($lang['DISABLED']);
 }