diff --git a/wp-includes/comment.php b/wp-includes/comment.php
index e2dfa18b8a..60692106b1 100644
--- a/wp-includes/comment.php
+++ b/wp-includes/comment.php
@@ -1580,7 +1580,7 @@ function update_comment_cache($comments) {
  * @return object
  */
 function _close_comments_for_old_posts( $posts ) {
-	if ( empty($posts) || !is_single() || !get_option('close_comments_for_old_posts') )
+	if ( empty($posts) || !is_singular() || !get_option('close_comments_for_old_posts') )
 		return $posts;
 
 	$days_old = (int) get_option('close_comments_days_old');