diff --git a/core/modules/node/node.pages.inc b/core/modules/node/node.pages.inc
index b2e1e4b..0d431d8 100644
--- a/core/modules/node/node.pages.inc
+++ b/core/modules/node/node.pages.inc
@@ -186,6 +186,29 @@ function theme_node_preview($variables) {
 }
 
 /**
+ * Preprocess variables for a node preview for display during node creation and editing.
+ */
+function template_preprocess_node_preview(&$variables) {
+  $node = $variables['node'];
+
+  // Render trimmed teaser version of the post.
+  $node_teaser = node_view(clone $node, 'teaser');
+  $variables['teaser']= drupal_render($node_teaser);
+  // Render full version of the post.
+  $node_full = node_view($node, 'full');
+  $variables['full'] = drupal_render($node_full);
+
+  if ($variables['teaser'] != $variables['full']) {
+    // Do we need to preview a trimmed teaser version of a post as well as a full version?
+    drupal_set_message(t('The trimmed version of your post shows what your post looks like when promoted to the main page or when exported for syndication.<span class="no-js"> You can insert the delimiter "&lt;!--break--&gt;" (without the quotes) to fine-tune where your post gets split.</span>'));
+    $variables['preview_teaser'] = TRUE;
+  }
+  else {
+    $variables['preview_teaser'] = FALSE;
+  }
+}
+
+/**
  * Page callback: Form constructor for node deletion confirmation form.
  *
  * @see node_menu()
diff --git a/core/themes/stark/templates/node/node-preview.html.twig b/core/themes/stark/templates/node/node-preview.html.twig
index f157e29..419b820 100644
--- a/core/themes/stark/templates/node/node-preview.html.twig
+++ b/core/themes/stark/templates/node/node-preview.html.twig
@@ -6,21 +6,21 @@
  * This display may be used during node creation and editing.
  *
  * Available variables:
- * - preview: Preview version of the node.
+ * - preview_teaser: Boolean flag indicating whether or not to show a trimmed teaser version.
+ * - teaser: Trimmed teaser version of the node.
  * - full: Full version of the node.
  *
  * @see template_preprocess
+ * @see template_preprocess_node_preview
  *
  * @ingroup themeable
  */
 #}
 <div class="node-preview-container">
-  {% if preview %}
+  {% if preview_teaser %}
     <h3>{{ "Preview trimmed version"|t }}</h3>
-    {{ preview }}
+    {{ teaser }}
     <h3>{{ "Preview full version"|t }}</h3>
-    {{ full }}
-  {% else %}
-    {{ full }}
   {% endif %}
+  {{ full }}
 </div>