diff --git a/types/File.d.ts b/types/File.d.ts
index 98bde8934..eb19cf68a 100644
--- a/types/File.d.ts
+++ b/types/File.d.ts
@@ -15,8 +15,9 @@ import { Options } from './Options';
 import { TransformedToken } from './TransformedToken';
 
 export interface File {
+  className?: string;
   destination: string;
   format?: string;
   filter?: string | Partial<TransformedToken> | ((token: TransformedToken) => boolean);
   options?: Options;
-}
\ No newline at end of file
+}