diff --git a/types/titanium/index.d.ts b/types/titanium/index.d.ts
index 8566aba21c..5fe1c391b3 100644
--- a/types/titanium/index.d.ts
+++ b/types/titanium/index.d.ts
@@ -19496,7 +19496,7 @@ declare namespace Titanium {
 			/**
 			 * Fires a synthesized event to any registered listeners.
 			 */
-			function fireEvent(name: string, event: any): void;
+			function fireEvent(name: string, event?: any): void;
 
 			/**
 			 * Applies the properties to the proxy.