diff --git a/src/utils/reactHelpers.d.ts b/src/utils/reactHelpers.d.ts
index 7e9d71294a9b0a..ba40215a9ce738 100644
--- a/src/utils/reactHelpers.d.ts
+++ b/src/utils/reactHelpers.d.ts
@@ -1,6 +1,15 @@
 import * as React from 'react';
+import { StandardProps } from '../';
 
 export function cloneChildrenWithClassName<T>(children: React.ReactNode, className: string): T[];
 
-export function isMuiElement(element: any, muiNames: Array<string>): boolean;
-export function isMuiComponent(element: any, muiNames: Array<string>): boolean;
+type NamedMuiComponent = React.ComponentType<{}> & { muiName: string };
+
+interface NamedMuiElement {
+  type: NamedMuiComponent;
+  props: StandardProps<{}, never>;
+  key: string | number | null;
+}
+
+export function isMuiElement(element: any, muiNames: string[]): element is NamedMuiElement;
+export function isMuiComponent(element: any, muiNames: string[]): element is NamedMuiComponent;