diff --git a/packages/node_modules/@node-red/nodes/core/function/90-exec.js b/packages/node_modules/@node-red/nodes/core/function/90-exec.js
index 47ab02eca..487166bcc 100644
--- a/packages/node_modules/@node-red/nodes/core/function/90-exec.js
+++ b/packages/node_modules/@node-red/nodes/core/function/90-exec.js
@@ -66,8 +66,9 @@ module.exports = function(RED) {
                 // then prepend with the msg.payload
                 var arg = node.cmd;
                 if (node.addpay) {
-                    if (msg.hasOwnProperty(node.addpayValue)) {
-                         arg += " " + RED.util.getMessageProperty(msg, node.addpayValue);
+                    var value = RED.util.getMessageProperty(msg, node.addpayValue);
+                    if (value !== undefined) {
+                        arg += " " + value;
                     }
                 }
                 if (node.append.trim() !== "") { arg += " " + node.append; }