diff --git a/react-modal/react-modal.d.ts b/react-modal/react-modal.d.ts
index 2aac95eacb..5171045c61 100644
--- a/react-modal/react-modal.d.ts
+++ b/react-modal/react-modal.d.ts
@@ -21,7 +21,9 @@ declare module "react-modal" {
         onRequestClose?: Function,
         closeTimeoutMS?: number,
         ariaHideApp?: boolean,
-        shouldCloseOnOverlayClick?: boolean
+        shouldCloseOnOverlayClick?: boolean,
+        overlayClassName?: string,
+        className?: string
     }
     let ReactModal: __React.ClassicComponentClass<ReactModal>;
     export = ReactModal;