diff --git a/lib/sinon/util/core/get-property-descriptor.js b/lib/sinon/util/core/get-property-descriptor.js
index 8dd3dc830..9625fd355 100644
--- a/lib/sinon/util/core/get-property-descriptor.js
+++ b/lib/sinon/util/core/get-property-descriptor.js
@@ -3,9 +3,15 @@
 module.exports = function getPropertyDescriptor(object, property) {
     var proto = object;
     var descriptor;
+    var isOwn = object && Object.getOwnPropertyDescriptor(object, property);
 
     while (proto && !(descriptor = Object.getOwnPropertyDescriptor(proto, property))) {
         proto = Object.getPrototypeOf(proto);
     }
+
+    if (descriptor) {
+        descriptor.isOwn = isOwn;
+    }
+
     return descriptor;
 };