diff --git a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
index 9e707fa68..f91a7c7d7 100644
--- a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
+++ b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
@@ -696,7 +696,7 @@ module.exports = function(RED) {
             // Ensure will payload, if set, is a string
             if (node.options.will && Object.hasOwn(node.options.will, 'payload')) {
                 let payload = node.options.will.payload
-                if (payload === null || payload === undefined) {
+                if (payload === null || typeof payload === 'undefined') {
                     payload = "";
                 } else if (!Buffer.isBuffer(payload)) {
                     if (typeof payload === "object") {