diff --git a/archiver/archiver.d.ts b/archiver/archiver.d.ts
index d5133555a4..b31c8ad619 100644
--- a/archiver/archiver.d.ts
+++ b/archiver/archiver.d.ts
@@ -24,7 +24,7 @@ declare module "archiver" {
         
     interface Archiver extends STREAM.Transform {
         pipe(writeStream: FS.WriteStream): void;
-        append(readStream: FS.ReadStream, name: nameInterface): void;
+        append(source: FS.ReadStream | Buffer | string, name: nameInterface): void;
         finalize(): void;
     }