diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 9500adf..621ff16 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -149,6 +149,7 @@ function system_theme() {
     ),
     'confirm_form' => array(
       'render element' => 'form',
+      'template' => 'confirm-form',
     ),
     'system_modules_details' => array(
       'render element' => 'form',
@@ -2849,22 +2850,6 @@ function system_run_automated_cron() {
 }
 
 /**
- * Returns HTML for a confirmation form.
- *
- * By default this does not alter the appearance of a form at all,
- * but is provided as a convenience for themers.
- *
- * @param $variables
- *   An associative array containing:
- *   - form: A render element representing the form.
- *
- * @ingroup themeable
- */
-function theme_confirm_form($variables) {
-  return drupal_render_children($variables['form']);
-}
-
-/**
  * Returns HTML for a system settings form.
  *
  * By default this does not alter the appearance of a form at all,
diff --git a/core/modules/system/templates/confirm-form.html.twig b/core/modules/system/templates/confirm-form.html.twig
new file mode 100644
index 0000000..c08eedf
--- /dev/null
+++ b/core/modules/system/templates/confirm-form.html.twig
@@ -0,0 +1,16 @@
+{#
+/**
+ * @file
+ * Template for confirm form..
+ *
+ * This template will be used when a confirm form specifies 'config_form'
+ * as its #theme callback.  Otherwise, by default, confirm forms will be
+ * themed by theme_form().
+ *
+ * Available variables:
+ * - form: The confirm form.
+ *
+ * @ingroup themeable
+ */
+#}
+{{ form }}