diff --git a/xml2js/index.d.ts b/xml2js/index.d.ts
index 0e180f7ba8..b23ebbbac2 100644
--- a/xml2js/index.d.ts
+++ b/xml2js/index.d.ts
@@ -8,8 +8,8 @@
 export = xml2js;
 
 declare namespace xml2js {
-    function parseString(xml: string, callback: (err: any, result: any) => void): void;
-    function parseString(xml: string, options: OptionsV2, callback: (err: any, result: any) => void): void;
+    function parseString(xml: convertableToString, callback: (err: any, result: any) => void): void;
+    function parseString(xml: convertableToString, options: OptionsV2, callback: (err: any, result: any) => void): void;
 
     var defaults: {
         '0.1': Options;
@@ -23,7 +23,7 @@ declare namespace xml2js {
 
     class Parser {
         constructor(options?: OptionsV2);
-        parseString(str: string, cb?: Function): void;
+        parseString(str: convertableToString, cb?: Function): void;
     }
 
     interface Options {
@@ -70,5 +70,9 @@ declare namespace xml2js {
         chunkSize?: number;
         cdata?: boolean;
     }
+
+    interface convertableToString {
+        toString(): string;
+    }
 }
 
diff --git a/xml2js/xml2js-tests.ts b/xml2js/xml2js-tests.ts
index 38306d9bb4..e0bea8cf9b 100644
--- a/xml2js/xml2js-tests.ts
+++ b/xml2js/xml2js-tests.ts
@@ -1,3 +1,4 @@
+/// <reference types="node"/>
 
 import xml2js = require('xml2js');
 
@@ -67,3 +68,11 @@ var v2Defaults = xml2js.defaults['0.2'];
 v2Defaults.async = false;
 v2Defaults.chunkSize = 20000;
 
+import fs = require('fs');
+ 
+fs.readFile(__dirname + '/foo.xml', function(err, data) {
+    parser.parseString(data, function (err: any, result: any) {
+        console.dir(result);
+        console.log('Done');
+    });
+});
\ No newline at end of file