diff --git a/chai/chai-tests.ts b/chai/chai-tests.ts
index 8a09c3f42..b559c515d 100644
--- a/chai/chai-tests.ts
+++ b/chai/chai-tests.ts
@@ -688,6 +688,12 @@ function _throw() {
     }, "blah: expected [Function] to throw error including 'hello' but got 'testing'");
 }
 
+function use(){
+    chai.use(function (_chai, utils) {
+      _chai.can.use.any();
+    });
+}
+
 function respondTo() {
     function Foo() {};
     var bar = {};
diff --git a/chai/chai.d.ts b/chai/chai.d.ts
index 9d649a17c..9fc93a667 100644
--- a/chai/chai.d.ts
+++ b/chai/chai.d.ts
@@ -8,6 +8,9 @@ declare module chai {
 
     function expect(target: any): Expect;
 
+    // Provides a way to extend the internals of Chai
+    function use(fn: (chai: any, utils: any) => void);
+
     interface ExpectStatic {
         (target: any): Expect;
     }