diff --git i/wp-includes/post-functions.php w/wp-includes/post-functions.php
index fdd01ee..8fc5843 100644
--- i/wp-includes/post-functions.php
+++ w/wp-includes/post-functions.php
@@ -425,8 +425,9 @@ function get_extended( $post ) {
  *                            When $output is OBJECT, a `WP_Post` instance is returned.
  */
 function get_post( $post = null, $output = OBJECT, $filter = 'raw' ) {
-	if ( empty( $post ) && isset( $GLOBALS['post'] ) )
+	if ( 0 !== $post && empty( $post ) && isset( $GLOBALS['post'] ) ) {
 		$post = $GLOBALS['post'];
+	}
 
 	if ( $post instanceof WP_Post ) {
 		$_post = $post;
@@ -443,15 +444,17 @@ function get_post( $post = null, $output = OBJECT, $filter = 'raw' ) {
 		$_post = WP_Post::get_instance( $post );
 	}
 
-	if ( ! $_post )
+	if ( ! $_post ) {
 		return null;
+	}
 
 	$_post = $_post->filter( $filter );
 
-	if ( $output == ARRAY_A )
+	if ( $output == ARRAY_A ) {
 		return $_post->to_array();
-	elseif ( $output == ARRAY_N )
+	} elseif ( $output == ARRAY_N ) {
 		return array_values( $_post->to_array() );
+	}
 
 	return $_post;
 }