diff --git a/types/ember/index.d.ts b/types/ember/index.d.ts
index 2e735a0..bd7300d 100644
--- a/types/ember/index.d.ts
+++ b/types/ember/index.d.ts
@@ -1340,7 +1340,7 @@ namespace Ember {
             the promise resolves, and the resolved value of the promise
             will be used as the model for this route.
         */
-        model(params: {}, transition: EmberStates.Transition): any | Rsvp.Promise<any, any>;
+        model(params?: {}, transition?: EmberStates.Transition): any | Rsvp.Promise<any, any>;
 
         /**
         Returns the model of a parent (or any ancestor) route