diff --git a/angular-ui-bootstrap/angular-ui-bootstrap.d.ts b/angular-ui-bootstrap/angular-ui-bootstrap.d.ts
index c3675e7a9..f6273dbd3 100644
--- a/angular-ui-bootstrap/angular-ui-bootstrap.d.ts
+++ b/angular-ui-bootstrap/angular-ui-bootstrap.d.ts
@@ -264,6 +264,11 @@ declare module angular.ui.bootstrap {
          */
         keyboard?: boolean;
 
+        /**
+         * additional CSS class(es) to be added to a modal backdrop template
+         */
+        backdropClass?: string;
+
         /**
          * additional CSS class(es) to be added to a modal window template
          */