diff --git a/commander/commander-tests.ts b/commander/commander-tests.ts
index f2457901da..135ad8bf02 100644
--- a/commander/commander-tests.ts
+++ b/commander/commander-tests.ts
@@ -95,6 +95,13 @@ program.on('--help', () => {
     console.log('');
 });
 
+program
+    .command('allow-unknown-option')
+    .allowUnknownOption()
+    .action(() => {
+        console.log('unknown option is allowed');
+    });
+
 program.parse(process.argv);
 
 console.log('stuff');
diff --git a/commander/commander.d.ts b/commander/commander.d.ts
index 09d7966596..278a491a62 100644
--- a/commander/commander.d.ts
+++ b/commander/commander.d.ts
@@ -158,6 +158,15 @@ declare module commander {
         option(flags:string, description?:string, fn?:(arg1:any, arg2:any)=>void, defaultValue?:any):ICommand;
         option(flags:string, description?:string, defaultValue?:any):ICommand;
 
+        /**
+         * Allow unknown options on the command line.
+         *
+         * @param {Boolean} arg if `true` or omitted, no error will be thrown
+         * for unknown options.
+         * @api public
+         */
+        allowUnknownOption(arg?: boolean):ICommand;
+
         /**
          * Parse `argv`, settings options and invoking commands when defined.
          *