diff --git a/wp-includes/post-thumbnail-template.php b/wp-includes/post-thumbnail-template.php
index 1377cc11b..65a517266 100644
--- a/wp-includes/post-thumbnail-template.php
+++ b/wp-includes/post-thumbnail-template.php
@@ -18,7 +18,6 @@
  * @return bool Whether post has an image attached.
  */
 function has_post_thumbnail( $post_id = null ) {
-	$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
 	return (bool) get_post_thumbnail_id( $post_id );
 }