diff --git a/src/tracker/index.js b/src/tracker/index.js
index 520d56eac..533a640a3 100644
--- a/src/tracker/index.js
+++ b/src/tracker/index.js
@@ -249,7 +249,7 @@
   };
 
   const identify = (data, id = undefined) => {
-    if (id) {
+    if (id && typeof id === 'string') {
       identity = id;
     }
     /* Clear cache since this will result in another session */