diff --git a/src/wp-admin/custom-background.php b/src/wp-admin/custom-background.php
index a23efda036..fd69447594 100644
--- a/src/wp-admin/custom-background.php
+++ b/src/wp-admin/custom-background.php
@@ -42,6 +42,11 @@ class Custom_Background {
 	 */
 	private $page = '';
 
+	/**
+	 * @var bool
+	 */
+	private $updated;
+
 	/**
 	 * Constructor - Register administration header callback.
 	 *