diff --git a/src/wp-admin/includes/class-wp-upgrader.php b/src/wp-admin/includes/class-wp-upgrader.php
index 221f0c0813..6db2c27725 100644
--- a/src/wp-admin/includes/class-wp-upgrader.php
+++ b/src/wp-admin/includes/class-wp-upgrader.php
@@ -1962,7 +1962,7 @@ class WP_Automatic_Updater {
 				break;
 			case 'theme':
 				$upgrader = new Theme_Upgrader( $skin );
-				$context  = get_theme_root( $item );
+				$context  = get_theme_root( $item->theme );
 				break;
 			case 'translation':
 				$upgrader = new Language_Pack_Upgrader( $skin );