diff --git a/deep-freeze/deep-freeze-tests.ts b/deep-freeze/deep-freeze-tests.ts
new file mode 100644
index 000000000..8369d3087
--- /dev/null
+++ b/deep-freeze/deep-freeze-tests.ts
@@ -0,0 +1,8 @@
+/// <reference path="deep-freeze.d.ts" />
+
+import df = require('deep-freeze');
+
+class Foo {
+	foo: string;
+}
+var foo:Foo = df(new Foo());
diff --git a/deep-freeze/deep-freeze.d.ts b/deep-freeze/deep-freeze.d.ts
new file mode 100644
index 000000000..3d7ede8ad
--- /dev/null
+++ b/deep-freeze/deep-freeze.d.ts
@@ -0,0 +1,9 @@
+// Type definitions for deep-freeze
+// Project: https://github.com/substack/deep-freeze
+// Definitions by: Bart van der Schoor <https://github.com/Bartvds>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+declare module 'deep-freeze' {
+	function df<T>(obj: T): T;
+	export = df;
+}