diff --git a/phpBB/includes/sessions.php b/phpBB/includes/sessions.php
index db6d52152e..bc6d0b5218 100644
--- a/phpBB/includes/sessions.php
+++ b/phpBB/includes/sessions.php
@@ -303,7 +303,7 @@ function session_pagestart($user_ip, $thispage_id)
 	// If we reach here then no (valid) session exists. So we'll create a new one,
 	// using the cookie user_id if available to pull basic user prefs.
 	//
-	$user_id = ( isset($sessiondata['userid']) ) ? $sessiondata['userid'] : ANONYMOUS;
+	$user_id = ( isset($sessiondata['userid']) ) ? intval($sessiondata['userid']) : ANONYMOUS;
 
 	if ( !($userdata = session_begin($user_id, $user_ip, $thispage_id, TRUE)) )
 	{