diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 486faa4e88..ae176bc510 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -741,6 +741,7 @@ class WP_Comment_Query {
 
 					case 'comment':
 					case 'comments':
+						$comment_types[ $operator ][] = "''";
 						$comment_types[ $operator ][] = "'comment'";
 						break;