diff --git a/addon/services/engine-router-service.js b/addon/services/engine-router-service.js
index f91881d..2515f44 100644
--- a/addon/services/engine-router-service.js
+++ b/addon/services/engine-router-service.js
@@ -6,6 +6,7 @@ import { getOwner } from '@ember/application';
 import Evented from '@ember/object/evented';
 import { namespaceEngineRouteName } from '../utils/namespace-engine-route-name';
 import { getRootOwner } from '../utils/root-owner';
+import { resemblesURL } from '../utils/resembles-url';
 
 export default class EngineRouterService extends Service.extend(Evented) {
   init() {
@@ -61,6 +62,10 @@ export default class EngineRouterService extends Service.extend(Evented) {
   }
 
   transitionTo(routeName, ...args) {
+    if (resemblesURL(routeName)) {
+      return get(this, 'externalRouter').transitionTo(routeName);
+    }
+
     return get(this, 'externalRouter').transitionTo(
       namespaceEngineRouteName(this._mountPoint, routeName),
       ...args
@@ -75,6 +80,10 @@ export default class EngineRouterService extends Service.extend(Evented) {
   }
 
   replaceWith(routeName, ...args) {
+    if (resemblesURL(routeName)) {
+      return get(this, 'externalRouter').replaceWith(routeName);
+    }
+
     return get(this, 'externalRouter').replaceWith(
       namespaceEngineRouteName(this._mountPoint, routeName),
       ...args
@@ -115,4 +124,4 @@ export default class EngineRouterService extends Service.extend(Evented) {
       ...args
     );
   }
-}
\ No newline at end of file
+}
diff --git a/addon/utils/resembles-url.js b/addon/utils/resembles-url.js
new file mode 100644
index 0000000..de1cbfc
--- /dev/null
+++ b/addon/utils/resembles-url.js
@@ -0,0 +1,11 @@
+/**
+ * Check if a routeName resembles a url.
+ *
+ * @public
+ * @method namespaceEngineRouteName
+ * @param {String} str
+ * @return {boolean}
+ */
+export function resemblesURL(str) {
+  return typeof str === 'string' && (str === '' || str[0] === '/');
+}
diff --git a/tests/acceptance/routeable-engine-demo-test.js b/tests/acceptance/routeable-engine-demo-test.js
index 4dc2858..21115fd 100644
--- a/tests/acceptance/routeable-engine-demo-test.js
+++ b/tests/acceptance/routeable-engine-demo-test.js
@@ -83,6 +83,23 @@ module('Acceptance | routeless engine demo', function (hooks) {
         find('.routable-is-active-external-button').classList.contains('is-active-external')
       );
     });
+
+    test('transitionTo with url transitions to the parent application from within an engine and returns a thenable Transition object', async function (
+      assert
+    ) {
+      assert.expect(2);
+
+      await visit('/');
+      await click('.routeable-engine');
+      await click('.blog-post-1-link-ch');
+      await click('.routable-transition-to-url-button');
+
+      assert.equal(currentURL(), '/routable-engine-demo/blog/post/2?lang=Korean');
+
+      assert.ok(
+        find('.routable-transition-to-url-button').classList.contains('transitioned-to-url')
+      );
+    });
   });
 
-});
\ No newline at end of file
+});
diff --git a/tests/dummy/lib/ember-blog/addon/controllers/post.js b/tests/dummy/lib/ember-blog/addon/controllers/post.js
index 33ca46a..7fbc950 100644
--- a/tests/dummy/lib/ember-blog/addon/controllers/post.js
+++ b/tests/dummy/lib/ember-blog/addon/controllers/post.js
@@ -28,6 +28,12 @@ export default Controller.extend({
       if (get(this, 'router').isActiveExternal('home')) {
         set(this, 'isActiveExternal', true);
       }
+    },
+
+    transitionToUrlByService(url) {
+      get(this, 'router').transitionTo(url).then(() => {
+        set(this, 'transitionTo', true);
+      });
     }
   }
-});
\ No newline at end of file
+});
diff --git a/tests/dummy/lib/ember-blog/addon/templates/post.hbs b/tests/dummy/lib/ember-blog/addon/templates/post.hbs
index 9715b0f..cd50916 100644
--- a/tests/dummy/lib/ember-blog/addon/templates/post.hbs
+++ b/tests/dummy/lib/ember-blog/addon/templates/post.hbs
@@ -50,3 +50,7 @@
 <button {{action "checkActiveState"}} class="routable-is-active-external-button {{if isActiveExternal 'is-active-external'}}">
     isActive in (Engine Router Service)
 </button>
+
+<button {{action "transitionToUrlByService" "/routable-engine-demo/blog/post/2?lang=Korean"}} class="routable-transition-to-url-button {{if transitionTo 'transitioned-to-url'}}">
+  Go to direct URL (Engine Router Service)
+</button>