diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index c150c29..2566cf9 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -691,8 +691,8 @@ public function prepareForm($form_id, &$form, &$form_state) {
 
     $form += $this->getElementInfo('form');
     $form += array('#tree' => FALSE, '#parents' => array());
-    $form['#validate'][] = array($form_state['build_info']['callback_object'], 'validateForm');
-    $form['#submit'][] = array($form_state['build_info']['callback_object'], 'submitForm');
+    $form['#validate'][] = 'validateForm';
+    $form['#submit'][] = 'submitForm';
 
     // If no #theme has been set, automatically apply theme suggestions.
     // theme_form() itself is in #theme_wrappers and not #theme. Therefore, the
diff --git a/core/lib/Drupal/Core/Form/FormSubmitter.php b/core/lib/Drupal/Core/Form/FormSubmitter.php
index 78aca72..9496ec7 100644
--- a/core/lib/Drupal/Core/Form/FormSubmitter.php
+++ b/core/lib/Drupal/Core/Form/FormSubmitter.php
@@ -129,6 +129,10 @@ public function executeSubmitHandlers(&$form, &$form_state) {
         $batch['has_form_submits'] = TRUE;
       }
       else {
+        // Support method names of the form object by converting.
+        if (is_string($function) && method_exists($form_state['build_info']['callback_object'], $function)) {
+          $function = array($form_state['build_info']['callback_object'], $function);
+        }
         call_user_func_array($function, array(&$form, &$form_state));
       }
     }
diff --git a/core/lib/Drupal/Core/Form/FormValidator.php b/core/lib/Drupal/Core/Form/FormValidator.php
index eda8238..92cdb61 100644
--- a/core/lib/Drupal/Core/Form/FormValidator.php
+++ b/core/lib/Drupal/Core/Form/FormValidator.php
@@ -69,6 +69,10 @@ public function executeValidateHandlers(&$form, &$form_state) {
     }
 
     foreach ($handlers as $function) {
+      // Support method names of the form object by converting.
+      if (is_string($function) && method_exists($form_state['build_info']['callback_object'], $function)) {
+        $function = array($form_state['build_info']['callback_object'], $function);
+      }
       call_user_func_array($function, array(&$form, &$form_state));
     }
   }
diff --git a/core/modules/user/src/ProfileTranslationHandler.php b/core/modules/user/src/ProfileTranslationHandler.php
index c332d83..c9b7125 100644
--- a/core/modules/user/src/ProfileTranslationHandler.php
+++ b/core/modules/user/src/ProfileTranslationHandler.php
@@ -20,7 +20,7 @@ class ProfileTranslationHandler extends ContentTranslationHandler {
    */
   public function entityFormAlter(array &$form, array &$form_state, EntityInterface $entity) {
     parent::entityFormAlter($form, $form_state, $entity);
-    $form['actions']['submit']['#submit'][] = array($this, 'entityFormSave');
+    $form['actions']['submit']['#submit'][] = 'entityFormSave';
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Form/FormSubmitterTest.php b/core/tests/Drupal/Tests/Core/Form/FormSubmitterTest.php
index cc34f74..bb3e60a 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormSubmitterTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormSubmitterTest.php
@@ -230,13 +230,16 @@ public function providerTestRedirectWithoutResult() {
    */
   public function testExecuteSubmitHandlers() {
     $form_submitter = $this->getFormSubmitter();
-    $mock = $this->getMock('stdClass', array('submit_handler', 'hash_submit'));
+    $mock = $this->getMock('stdClass', array('submit_handler', 'hash_submit', 'simple_string_submit'));
     $mock->expects($this->once())
       ->method('submit_handler')
       ->with($this->isType('array'), $this->isType('array'));
     $mock->expects($this->once())
       ->method('hash_submit')
       ->with($this->isType('array'), $this->isType('array'));
+    $mock->expects($this->once())
+      ->method('simple_string_submit')
+      ->with($this->isType('array'), $this->isType('array'));
 
     $form = array();
     $form_state = $this->getFormStateDefaults();
@@ -248,6 +251,12 @@ public function testExecuteSubmitHandlers() {
     // $form_state submit handlers will supersede $form handlers.
     $form_state['submit_handlers'][] = array($mock, 'submit_handler');
     $form_submitter->executeSubmitHandlers($form, $form_state);
+
+    // Methods directly on the form object can be specified as a string.
+    $form_state = $this->getFormStateDefaults();
+    $form_state['build_info']['callback_object'] = $mock;
+    $form_state['submit_handlers'][] = 'simple_string_submit';
+    $form_submitter->executeSubmitHandlers($form, $form_state);
   }
 
   /**