diff --git a/lib/mixpanel-node.d.ts b/lib/mixpanel-node.d.ts
index fe91139..838acb6 100644
--- a/lib/mixpanel-node.d.ts
+++ b/lib/mixpanel-node.d.ts
@@ -24,6 +24,7 @@ declare namespace mixpanel {
     keepAlive: boolean;
     geolocate: boolean;
     logger: CustomLogger;
+    secret: string;
   }
 
   export interface PropertyDict {