diff --git a/mithril/mithril.d.ts b/mithril/mithril.d.ts
index 3b9690080..e01dbcc02 100644
--- a/mithril/mithril.d.ts
+++ b/mithril/mithril.d.ts
@@ -8,7 +8,8 @@
 interface MithrilStatic {
 	(selector: string, attributes: Object, children?: any): MithrilVirtualElement;
 	(selector: string, children?: any): MithrilVirtualElement;
-	prop<T>(value?: T): (value?: T) => T;
+    prop<T>(value?: T): (value?: T) => T;
+    prop<T>(promise: MithrilPromise<T>): MithrilPromiseProperty<T>;
 	withAttr(property: string, callback: (value: any) => void): (e: Event) => any;
 	module(rootElement: Node, module: MithrilModule): void;
 	trust(html: string): String;
@@ -52,6 +53,13 @@ interface MithrilDeferred<T> {
 interface MithrilPromise<T> {
     (value?: T): T;
     then<R>(successCallback?: (value: T) => R, errorCallback?: (value: any) => any): MithrilPromise<R>;
+    then<R>(successCallback?: (value: T) => MithrilPromise<R>, errorCallback?: (value: any) => any): MithrilPromise<R>;
+}
+
+interface MithrilPromiseProperty<T> extends MithrilPromise<T> {
+    (): T;
+    (value: T): T;
+    toJSON(): T;
 }
 
 interface MithrilXHROptions {