diff --git a/wp-admin/admin-header.php b/wp-admin/admin-header.php
index 9e15168527..3252a09951 100644
--- a/wp-admin/admin-header.php
+++ b/wp-admin/admin-header.php
@@ -85,7 +85,8 @@ $admin_body_class .= ' version-' . str_replace( '.', '-', preg_replace( '/^([.0-
 $admin_body_class .= ' admin-color-' . sanitize_html_class( get_user_option( 'admin_color' ), 'fresh' );
 $admin_body_class .= ' locale-' . sanitize_html_class( strtolower( str_replace( '_', '-', get_locale() ) ) );
 
-if ( false !== $post_format = get_post_format() ) {
+if ( isset( $post ) && is_a( $post, 'WP_Post' ) && post_type_supports( get_post_type(), 'post-formats' ) ) {
+	$post_format = get_post_format();
 	if ( ! $post_format ) {
 		$post_format = 'standard';