diff --git a/core/modules/datetime/datetime.module b/core/modules/datetime/datetime.module
index 51e74f8..b23d7d2 100644
--- a/core/modules/datetime/datetime.module
+++ b/core/modules/datetime/datetime.module
@@ -1139,8 +1139,11 @@ function datetime_range_years($string, $date = NULL) {
 function datetime_form_node_form_alter(&$form, &$form_state, $form_id) {
   // Alter the 'Authored on' date to use datetime.
   $form['author']['date']['#type'] = 'datetime';
-  $form['author']['date']['#description'] = t('Format: %format. Leave blank to use the time of form submission.', array('%format' => datetime_format_example($date_format)));
+  $form['author']['date'] += element_info('datetime');
   unset($form['author']['date']['#maxlength']);
+
+  $format = trim(datetime_html5_format('date', $form['author']['date']) . ' ' . datetime_html5_format('time', $form['author']['date']));
+  $form['author']['date']['#description'] = t('Format: %format. Leave blank to use the time of form submission.', array('%format' => datetime_format_example($format)));
 }
 
 /**
diff --git a/core/modules/node/lib/Drupal/node/NodeFormController.php b/core/modules/node/lib/Drupal/node/NodeFormController.php
index 6fa84ef..98a827f 100644
--- a/core/modules/node/lib/Drupal/node/NodeFormController.php
+++ b/core/modules/node/lib/Drupal/node/NodeFormController.php
@@ -44,8 +44,8 @@ protected function prepareEntity() {
     else {
       $config = \Drupal::config('system.date');
       $format_type = datetime_default_format_type();
-      $date_format = $config->get('formats.html_date.pattern.' . $format_type) . ' ' . $config->get('formats.html_time.pattern.' . $format_type);
-      $node->date = format_date($node->created, 'custom', $date_format);
+      $format = $config->get('formats.html_date.pattern.' . $format_type) . ' ' . $config->get('formats.html_time.pattern.' . $format_type);
+      $node->date = format_date($node->created, 'custom', $format);
       // Remove the log message from the original node entity.
       $node->log = NULL;
     }
@@ -193,12 +193,12 @@ public function form(array $form, array &$form_state) {
     );
     $config = \Drupal::config('system.date');
     $format_type = datetime_default_format_type();
-    $date_format = $config->get('formats.html_date.pattern.' . $format_type) . ' ' . $config->get('formats.html_time.pattern.' . $format_type);
+    $format = $config->get('formats.html_date.pattern.' . $format_type) . ' ' . $config->get('formats.html_time.pattern.' . $format_type);
     $form['author']['date'] = array(
       '#type' => 'textfield',
       '#title' => t('Authored on'),
       '#maxlength' => 25,
-      '#description' => t('Format: %format. Leave blank to use the time of form submission.', array('%format' => $date_format)),
+      '#description' => t('Format: %format. Leave blank to use the time of form submission.', array('%format' => $format)),
       '#default_value' => !empty($node->date) ? $node->date : '',
     );