diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 2b06429..22616e1 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2371,16 +2371,10 @@ function template_preprocess_field(&$variables, $hook) {
   // Add default CSS classes. Since there can be many fields rendered on a page,
   // save some overhead by calling strtr() directly instead of
   // drupal_html_class().
-  $variables['entity_type_css'] = strtr($element['#entity_type'], '_', '-');
-  $variables['field_name_css'] = strtr($element['#field_name'], '_', '-');
-  $variables['field_type_css'] = strtr($element['#field_type'], '_', '-');
-  $variables['attributes']['class'] = array(
-    'field',
-    'field-' . $variables['entity_type_css'] . '--' . $variables['field_name_css'],
-    'field-name-' . $variables['field_name_css'],
-    'field-type-' . $variables['field_type_css'],
-    'field-label-' . $element['#label_display'],
-  );
+  $variables['css_entity_type'] = strtr($element['#entity_type'], '_', '-');
+  $variables['css_field_name'] = strtr($element['#field_name'], '_', '-');
+  $variables['css_field_type'] = strtr($element['#field_type'], '_', '-');
+  $variables['css_label_display'] = strtr($element['#label_display'], '_', '-');
   // Add a "clearfix" class to the wrapper since we float the label and the
   // field items in field.module.css if the label is inline.
   if ($element['#label_display'] == 'inline') {
diff --git a/core/modules/system/templates/field.html.twig b/core/modules/system/templates/field.html.twig
index a0d527a..19a97b6 100644
--- a/core/modules/system/templates/field.html.twig
+++ b/core/modules/system/templates/field.html.twig
@@ -16,20 +16,23 @@
  * - field.html.twig
  *
  * Available variables:
- * - attributes: HTML attributes for the containing element.
  * - label_hidden: Whether to show the field label or not.
  * - title_attributes: HTML attributes for the title.
  * - label: The label for the field.
  * - content_attributes: HTML attributes for the content.
  * - items: List of all the field items.
  * - item_attributes: List of HTML attributes for each item.
- *
+ * - attributes: HTML attributes for the containing element.
+ * - css_entity_type: The entity type to which the field belongs, in a CSS friendly format.
+ * - css_field_name: The name of the field, in a CSS friendly format.
+ * - css_field_type: The type of the field, in a CSS friendly format.
+ * - css_label_display: The display of the label for the field, in a CSS friendly format..
  * @see template_preprocess_field()
  *
  * @ingroup themeable
  */
 #}
-<div{{ attributes }}>
+<div class="field field-{{ css_entity_type }}--{{ css_field_name }} field-name-{{ css_field_name }} field-type-{{ css_field_type }} field-label-{{ css_label_display }}{{ (attributes.class is defined) ? ' ' ~ attributes.class  : '' }}"{{ attributes }}>
   {% if not label_hidden %}
     <div class="field-label"{{ title_attributes }}>{{ label }}:&nbsp;</div>
   {% endif %}