diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index cc277c5..d0f860f 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -360,61 +360,29 @@ function theme_get_setting($setting_name, $theme = NULL) {
 }
 
 /**
- * Helper function to automatically escape variables in theme functions.
+ * Helper function to escape and render variables in theme functions.
  *
- * You use this method in theme functions to ensure that the result is safe.
- * This mimics the behavior of the autoescape in Twig.
- *
- * @see \Drupal\Core\Template\TwigExtension::escapeFilter()
+ * Use this method in theme functions to ensure that the result is safe for
+ * output inside HTML fragments. This mimics the behavior of the auto-escape
+ * functionality in Twig.
  *
  * @param mixed $arg
- *   The string, object, or render array to escape if needed.
+ *   The string, object, or render array to escape and render.
  *
  * @return string
- *   HTML string.
+ *   The rendered string.
+ *
+ * @see \Drupal\Core\Template\TwigExtension::escapeFilter()
  */
-function theme_autoescape($arg) {
-  // @see
-  if ($arg instanceOf SafeStringInterface) {
-    return (string) $arg;
-  }
-  $return = NULL;
-
-  if (is_scalar($arg)) {
-    $return = (string) $arg;
-  }
-  elseif (is_object($arg)) {
-    if ($arg instanceof RenderableInterface) {
-      $arg = $arg->toRenderable();
-    }
-    elseif (method_exists($arg, '__toString')) {
-      $return = (string) $arg;
-    }
-    // You can't throw exceptions in the magic PHP __toString methods, see
-    // http://php.net/manual/en/language.oop5.magic.php#object.tostring so
-    // we also support a toString method.
-    elseif (method_exists($arg, 'toString')) {
-      $return = $arg->toString();
-    }
-    else {
-      throw new \Exception(t('Object of type "@class" cannot be printed.', array('@class' => get_class($arg))));
-    }
-  }
-
-  // We have a string or an object converted to a string: Autoescape it!
-  if (isset($return)) {
-    return SafeMarkup::isSafe($return, 'html') ? $return:  Html::escape($return);
-  }
-
-  // This is a normal render array, which is safe by definition, with
-  // special simple cases already handled.
+function theme_escape_and_render($arg) {
+  /** @var \Drupal\Core\Template\TwigEnvironment $environment */
+  $environment = \Drupal::service('twig');
 
-  // Early return if this element was pre-rendered (no need to re-render).
-  if (isset($arg['#printed']) && $arg['#printed'] == TRUE && isset($arg['#markup']) && strlen($arg['#markup']) > 0) {
-    return (string) $arg['#markup'];
+  $return = \Drupal::service('twig.extension')->escapeFilter($environment, $arg, 'html', NULL, TRUE);
+  if ($return instanceof SafeStringInterface) {
+    $return = (string) $return;
   }
-  $arg['#printed'] = FALSE;
-  return (string) \Drupal::service('renderer')->render($arg);
+  return $return;
 }
 
 /**
diff --git a/core/tests/Drupal/KernelTests/Core/Theme/ThemeAutoescapeTest.php b/core/tests/Drupal/KernelTests/Core/Theme/ThemeAutoescapeTest.php
index 7cfaba1..afacc4b 100644
--- a/core/tests/Drupal/KernelTests/Core/Theme/ThemeAutoescapeTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Theme/ThemeAutoescapeTest.php
@@ -20,14 +20,6 @@
 class ThemeAutoescapeTest extends KernelTestBase {
 
   /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = [];
-
-
-  /**
    * Tests automatic escaping.
    *
    * @dataProvider providerTestThemeAutoescape
@@ -37,7 +29,7 @@ public function testThemeAutoescape($arg, $expected) {
     $renderer = \Drupal::service('renderer');
     $context = new RenderContext();
     $renderer->executeInRenderContext($context, function() use ($expected, $arg) {
-      $this->assertSame($expected, theme_autoescape($arg));
+      $this->assertSame($expected, theme_escape_and_render($arg));
     });
   }
 
@@ -46,11 +38,11 @@ public function testThemeAutoescape($arg, $expected) {
    */
   public function providerTestThemeAutoescape() {
     return [
-      ['', ''],
+      ['', NULL],
       ['a', 'a'],
       ['>', '>'],
-      [SafeString::create('<em>hi</em>'), '<em>hi</em>'],
-      [['#markup' => '<em>hi</em>'], '<em>hi</em>'],
+      [SafeString::create('<script>hi</script>'), '<script>hi</script>'],
+      [['#markup' => '<script>hi</script>'], '<script>hi</script>'],
       ['<script>alert(123)</script>', Html::escape('<script>alert(123)</script>')],
     ];
   }