diff --git a/packages/core/src/debug/debug_node.ts b/packages/core/src/debug/debug_node.ts
index f4ecc218c2..e8547d8783 100644
--- a/packages/core/src/debug/debug_node.ts
+++ b/packages/core/src/debug/debug_node.ts
@@ -638,14 +638,19 @@ function getDebugNode__PRE_R3__(nativeNode: any): DebugNode|null {
   return _nativeNodeToDebugNode.get(nativeNode) || null;
 }
 
+const NG_DEBUG_PROPERTY = '__ng_debug__';
+
 export function getDebugNode__POST_R3__(nativeNode: Element): DebugElement__POST_R3__;
 export function getDebugNode__POST_R3__(nativeNode: Node): DebugNode__POST_R3__;
 export function getDebugNode__POST_R3__(nativeNode: null): null;
 export function getDebugNode__POST_R3__(nativeNode: any): DebugNode|null {
   if (nativeNode instanceof Node) {
-    return nativeNode.nodeType == Node.ELEMENT_NODE ?
-        new DebugElement__POST_R3__(nativeNode as Element) :
-        new DebugNode__POST_R3__(nativeNode);
+    if (!(nativeNode.hasOwnProperty(NG_DEBUG_PROPERTY))) {
+      (nativeNode as any)[NG_DEBUG_PROPERTY] = nativeNode.nodeType == Node.ELEMENT_NODE ?
+          new DebugElement__POST_R3__(nativeNode as Element) :
+          new DebugNode__POST_R3__(nativeNode);
+    }
+    return (nativeNode as any)[NG_DEBUG_PROPERTY];
   }
   return null;
 }
@@ -678,9 +683,9 @@ export interface Predicate<T> { (value: T): boolean; }
 /**
  * @publicApi
  */
-export const DebugNode: {new (...args: any[]): DebugNode} = DebugNode__PRE_R3__ as any;
+export const DebugNode: {new (...args: any[]): DebugNode} = DebugNode__PRE_R3__;
 
 /**
  * @publicApi
  */
-export const DebugElement: {new (...args: any[]): DebugElement} = DebugElement__PRE_R3__ as any;
+export const DebugElement: {new (...args: any[]): DebugElement} = DebugElement__PRE_R3__;
diff --git a/packages/core/test/debug/debug_node_spec.ts b/packages/core/test/debug/debug_node_spec.ts
index ac3773b873..b45cb43031 100644
--- a/packages/core/test/debug/debug_node_spec.ts
+++ b/packages/core/test/debug/debug_node_spec.ts
@@ -7,7 +7,7 @@
  */
 
 
-import {Component, Directive, ElementRef, EmbeddedViewRef, EventEmitter, HostBinding, Injectable, Input, NO_ERRORS_SCHEMA, TemplateRef, ViewChild, ViewContainerRef} from '@angular/core';
+import {Component, DebugNode, Directive, ElementRef, EmbeddedViewRef, EventEmitter, HostBinding, Injectable, Input, NO_ERRORS_SCHEMA, TemplateRef, ViewChild, ViewContainerRef} from '@angular/core';
 import {ComponentFixture, TestBed, async} from '@angular/core/testing';
 import {By} from '@angular/platform-browser/src/dom/debug/by';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
@@ -678,5 +678,22 @@ class TestCmptWithPropBindings {
       expect(divB.nativeElement.getAttribute('id')).toBe('b');
     });
 
+    it('should be an instance of DebugNode', () => {
+      fixture = TestBed.createComponent(ParentComp);
+      fixture.detectChanges();
+      expect(fixture.debugElement).toBeAnInstanceOf(DebugNode);
+    });
+
+    it('should return the same element when queried twice', () => {
+      fixture = TestBed.createComponent(ParentComp);
+      fixture.detectChanges();
+
+      const childTestElsFirst = fixture.debugElement.queryAll(By.css('child-comp'));
+      const childTestElsSecond = fixture.debugElement.queryAll(By.css('child-comp'));
+
+      expect(childTestElsFirst.length).toBe(1);
+      expect(childTestElsSecond[0]).toBe(childTestElsFirst[0]);
+    });
+
   });
 }