diff --git a/gulp-file-include/index.d.ts b/gulp-file-include/index.d.ts
index 546225cd03..9b3acb7d89 100644
--- a/gulp-file-include/index.d.ts
+++ b/gulp-file-include/index.d.ts
@@ -5,7 +5,8 @@
 
 /// <reference types="node" />
 
-declare function fileinclude(): NodeJS.ReadWriteStream;
+declare function fileinclude(prefix: string): NodeJS.ReadWriteStream;
+declare function fileinclude(opts: fileinclude.Options): NodeJS.ReadWriteStream;
 declare namespace fileinclude {
     export interface Options {
         /** default: "@@" */