diff --git a/sinon-chrome/sinon-chrome.d.ts b/sinon-chrome/sinon-chrome.d.ts
index eddb32be4..f5aa2344f 100644
--- a/sinon-chrome/sinon-chrome.d.ts
+++ b/sinon-chrome/sinon-chrome.d.ts
@@ -411,6 +411,7 @@ declare module SinonChrome.runtime {
 
     export var id: string;
     export var getURL: Sinon.SinonSpy;
+    export var lastError: { message?: string };
 }
 
 declare module SinonChrome.sessions {