diff --git a/classes/Profile.php b/classes/Profile.php
index ea87d217ab..fe2ce343d7 100644
--- a/classes/Profile.php
+++ b/classes/Profile.php
@@ -745,7 +745,7 @@ class Profile extends Managed_DataObject
      * @param Profile $other
      * @return boolean
      */
-    function isSubscribed($other)
+    function isSubscribed(Profile $other)
     {
         return Subscription::exists($this, $other);
     }
diff --git a/classes/User.php b/classes/User.php
index a6b04d5905..2b390bb90b 100644
--- a/classes/User.php
+++ b/classes/User.php
@@ -134,7 +134,7 @@ class User extends Managed_DataObject
         return $this->_profile;
     }
 
-    function isSubscribed($other)
+    function isSubscribed(Profile $other)
     {
         return $this->getProfile()->isSubscribed($other);
     }