diff --git a/lib/Models/Subscriber.php b/lib/Models/Subscriber.php
index 3c9073d37b..dbdb190432 100644
--- a/lib/Models/Subscriber.php
+++ b/lib/Models/Subscriber.php
@@ -101,7 +101,7 @@ class Subscriber extends Model {
   }
 
   function isWPUser() {
-    return ($this->wp_user_id !== null);
+    return (bool)$this->wp_user_id;
   }
 
   function isWooCommerceUser() {