diff --git a/src/core/instance/lifecycle.js b/src/core/instance/lifecycle.js
index fd01d510865..db7bf286f11 100644
--- a/src/core/instance/lifecycle.js
+++ b/src/core/instance/lifecycle.js
@@ -133,6 +133,10 @@ export function lifecycleMixin (Vue: Class<Component>) {
     if (vm.$el) {
       vm.$el.__vue__ = null
     }
+    // release circular reference (#6759)
+    if (vm.$vnode) {
+      vm.$vnode.parent = null
+    }
   }
 }