diff --git a/types/backbone-relational/backbone-relational-tests.ts b/types/backbone-relational/backbone-relational-tests.ts
index 90433cd153..6e0135fcd9 100644
--- a/types/backbone-relational/backbone-relational-tests.ts
+++ b/types/backbone-relational/backbone-relational-tests.ts
@@ -74,6 +74,7 @@ paul.get('livesIn'); // === ourHouse
 // You can control which relations get serialized to JSON, using the 'includeInJSON'
 // property on a Relation. Also, each object will only get serialized once to prevent loops.
 alert(JSON.stringify(paul.get('user').toJSON(), null, '\t'));
+alert(JSON.stringify(paul.get('user').toJSON({ option1: 'value1' }), null, '\t'));
 // Load occupants 'person-2' and 'person-5', which don't exist yet, from the server
 ourHouse.fetchRelated('occupants');
 
diff --git a/types/backbone-relational/index.d.ts b/types/backbone-relational/index.d.ts
index 403759ac97..84406fb60a 100644
--- a/types/backbone-relational/index.d.ts
+++ b/types/backbone-relational/index.d.ts
@@ -34,7 +34,7 @@ declare module 'backbone' {
 
         fetchRelated(key:string, options?:any, update?:boolean):any;
 
-        toJSON():any;
+        toJSON(options?: any):any;
 
         static setup();