diff --git a/libraries/joomla/user/user.php b/libraries/joomla/user/user.php
index 58b88dd6a5e59..af2dc31e2fc0c 100644
--- a/libraries/joomla/user/user.php
+++ b/libraries/joomla/user/user.php
@@ -264,6 +264,13 @@ public static function getInstance($identifier = 0)
 			$id = $identifier;
 		}
 
+		// If the $id is zero, just return an empty JUser.
+		// Note: don't cache this user because it'll have a new ID on save!
+		if ($id === 0)
+		{
+			return new JUser;
+		}
+
 		if (empty(self::$instances[$id]))
 		{
 			$user = new JUser($id);