diff --git a/knockout/knockout-2.2.d.ts b/knockout/knockout-2.2.d.ts
index 0598e64e86..6a40a8112a 100644
--- a/knockout/knockout-2.2.d.ts
+++ b/knockout/knockout-2.2.d.ts
@@ -289,6 +289,7 @@ interface KnockoutStatic {
     toJSON(viewModel: any, replacer?: Function, space?: any): string;
     toJS(viewModel: any): any;
     isObservable(instance: any): bool;
+    isComputed(instance: any): bool;
     dataFor(node: any): any;
     removeNode(node: Element);
     cleanNode(node: Element);