diff --git a/knockout/knockout.d.ts b/knockout/knockout.d.ts
index b9c1e9cb7b..5614d9d493 100644
--- a/knockout/knockout.d.ts
+++ b/knockout/knockout.d.ts
@@ -133,6 +133,8 @@ interface KnockoutBindingHandler {
 }
 
 interface KnockoutBindingHandlers {
+    [bindingHandler: string]: KnockoutBindingHandler;
+
     // Controlling text and appearance
     visible: KnockoutBindingHandler;
     text: KnockoutBindingHandler;