diff --git a/packages/react/src/components/ContextualMenu/ContextualMenu.base.tsx b/packages/react/src/components/ContextualMenu/ContextualMenu.base.tsx
index 945165847f8d70..c457e42be1a7fd 100644
--- a/packages/react/src/components/ContextualMenu/ContextualMenu.base.tsx
+++ b/packages/react/src/components/ContextualMenu/ContextualMenu.base.tsx
@@ -149,7 +149,7 @@ const _getMenuItemStylesFunction = memoizeFunction(
     ...styles: (IStyleFunctionOrObject<IContextualMenuItemStyleProps, IContextualMenuItemStyles> | undefined)[]
   ): IStyleFunctionOrObject<IContextualMenuItemStyleProps, IContextualMenuItemStyles> => {
     return (styleProps: IContextualMenuItemStyleProps) =>
-      concatStyleSetsWithProps(styleProps, getItemStyles, ...styles);
+      concatStyleSetsWithProps(styleProps, getItemStyles, ...styles) as IContextualMenuItemStyles;
   },
 );