diff --git a/wp-includes/wp-db.php b/wp-includes/wp-db.php
index 39e9331692..602ab991d6 100644
--- a/wp-includes/wp-db.php
+++ b/wp-includes/wp-db.php
@@ -113,9 +113,9 @@ class wpdb {
 	 * Last query made
 	 *
 	 * @since 0.71
-	 * @var array
+	 * @var string
 	 */
-	var $last_query;
+	var $last_query = '';
 
 	/**
 	 * Results of the last query made