diff --git a/types/browserify/browserify-tests.ts b/types/browserify/browserify-tests.ts
index 2a1da315ed..c256d81ca3 100644
--- a/types/browserify/browserify-tests.ts
+++ b/types/browserify/browserify-tests.ts
@@ -60,3 +60,6 @@ Object.keys(insertGlobals.vars).forEach((x) => {
 var b = browserify('./browser/main.js', {
   insertGlobalVars: insertGlobalVars
 });
+
+declare const file: string | string[];
+b.add(file);
diff --git a/types/browserify/index.d.ts b/types/browserify/index.d.ts
index e419fa2ceb..f9fb6aa3d8 100644
--- a/types/browserify/index.d.ts
+++ b/types/browserify/index.d.ts
@@ -1,6 +1,9 @@
 // Type definitions for Browserify 12.0
 // Project: http://browserify.org/
-// Definitions by: Andrew Gaspar <https://github.com/AndrewGaspar>, John Vilk <https://github.com/jvilk>, Leonard Thieu <https://github.com/leonard-thieu>
+// Definitions by: Andrew Gaspar <https://github.com/AndrewGaspar>
+//                 John Vilk <https://github.com/jvilk>
+//                 Leonard Thieu <https://github.com/leonard-thieu>
+//                 Linus Unnebäck <https://github.com/LinusU>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 /// <reference types="node" />
@@ -102,8 +105,7 @@ interface BrowserifyObject extends NodeJS.EventEmitter {
    * Add an entry file from file that will be executed when the bundle loads.
    * If file is an array, each item in file will be added as an entry file.
    */
-  add(file: InputFile[], opts?: FileOptions): BrowserifyObject;
-  add(file: InputFile, opts?: FileOptions): BrowserifyObject;
+  add(file: InputFile | InputFile[], opts?: FileOptions): BrowserifyObject;
   /**
    * Make file available from outside the bundle with require(file).
    * The file param is anything that can be resolved by require.resolve().