diff --git a/wp-includes/comment-template.php b/wp-includes/comment-template.php
index 79b51c1a98..f8ebaecdcc 100644
--- a/wp-includes/comment-template.php
+++ b/wp-includes/comment-template.php
@@ -433,10 +433,13 @@ function comment_class( $class = '', $comment = null, $post_id = null, $echo = t
 function get_comment_class( $class = '', $comment_id = null, $post_id = null ) {
 	global $comment_alt, $comment_depth, $comment_thread_alt;
 
-	$comment = get_comment($comment_id);
-
 	$classes = array();
 
+	$comment = get_comment( $comment_id );
+	if ( ! $comment ) {
+		return $classes;
+	}
+
 	// Get the comment type (comment, trackback),
 	$classes[] = ( empty( $comment->comment_type ) ) ? 'comment' : $comment->comment_type;
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 6d8462be14..cecbb45fbd 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-34453';
+$wp_version = '4.4-alpha-34454';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.