diff --git a/src/wp-includes/comment-functions.php b/src/wp-includes/comment-functions.php
index 2c399e7c43..949453e159 100644
--- a/src/wp-includes/comment-functions.php
+++ b/src/wp-includes/comment-functions.php
@@ -1737,7 +1737,7 @@ function wp_new_comment_notify_postauthor( $comment_ID ) {
 	}
 
 	// Only send notifications for approved comments.
-	if ( 'spam' === $comment->comment_approved || ! $comment->comment_approved ) {
+	if ( ! isset( $comment->comment_approved ) || 'spam' === $comment->comment_approved || ! $comment->comment_approved ) {
 		return false;
 	}