diff --git a/core/lib/Drupal/Core/Field/ComputedFieldItemListBase.php b/core/lib/Drupal/Core/Field/ComputedFieldItemListBase.php
new file mode 100644
index 0000000..8bd789d
--- /dev/null
+++ b/core/lib/Drupal/Core/Field/ComputedFieldItemListBase.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace Drupal\Core\Field;
+
+abstract class ComputedFieldItemListBase extends FieldItemList implements FieldItemListInterface {
+
+  /**
+   * @return mixed
+   */
+  abstract protected function computeFieldItemListValues();
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($index) {
+    $this->computeFieldItemListValues();
+    $errors = $this->validate()->getIterator();
+    if ($errors->current()) {
+      throw new FieldException($errors->current()->getMessage());
+    }
+    return isset($this->list[$index]) ? $this->list[$index] : NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIterator() {
+    $this->computeFieldItemListValues();
+    return parent::getIterator();
+  }
+}
diff --git a/core/modules/field/tests/modules/field_computed_test/field_computed_test.info.yml b/core/modules/field/tests/modules/field_computed_test/field_computed_test.info.yml
new file mode 100644
index 0000000..42f6216
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/field_computed_test.info.yml
@@ -0,0 +1,6 @@
+name: 'Field Computed Test'
+type: module
+description: 'Support module for the computed field tests.'
+core: 8.x
+package: Testing
+version: VERSION
diff --git a/core/modules/field/tests/modules/field_computed_test/field_computed_test.module b/core/modules/field/tests/modules/field_computed_test/field_computed_test.module
new file mode 100644
index 0000000..6a29dd7
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/field_computed_test.module
@@ -0,0 +1,63 @@
+<?php
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\field_computed_test\Plugin\Field\FieldType\ComputedValuesItemList;
+
+
+
+
+/**
+ * Implements hook_entity_bundle_field_info().
+ *
+ * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+ * @param $bundle
+ * @param array $fields
+ *
+ * @return array
+ */
+function field_computed_test_entity_bundle_field_info(EntityTypeInterface $entity_type, $bundle, array $fields) {
+
+  if ($entity_type->id() === 'entity_test') {
+
+    // Add fields to separate bundles so we can test them individually.
+    switch ($bundle) {
+      case 'valid_computed_timestamp':
+        $fields['valid_computed_timestamp'] = BaseFieldDefinition::create('timestamp')
+          ->setComputed(TRUE)
+          ->setClass(ComputedValuesItemList::class)
+          ->setSetting('field', 'valid_computed_timestamp')
+          ->setLabel(t('Request Time'));
+        break;
+      case 'valid_computed_entity_reference':
+        $fields['valid_computed_entity_reference'] = BaseFieldDefinition::create('entity_reference')
+          ->setComputed(TRUE)
+          ->setSetting('target_type', 'entity_test')
+          ->setClass(ComputedValuesItemList::class)
+          ->setSetting('field', 'valid_computed_entity_reference')
+          ->setLabel(t('Valid Computed Entity Reference'));
+        break;
+      case 'non_valid_computed_timestamp':
+        $fields['non_valid_computed_timestamp'] = BaseFieldDefinition::create('timestamp')
+          ->setComputed(TRUE)
+          ->setClass(ComputedValuesItemList::class)
+          ->setSetting('field', 'non_valid_computed_timestamp')
+          ->setLabel(t('Non valid computed integer'));
+        break;
+      case 'non_valid_computed_entity_reference':
+        $fields['non_valid_computed_entity_reference'] = BaseFieldDefinition::create('entity_reference')
+          ->setComputed(TRUE)
+          ->setSetting('target_type', 'entity_test')
+          ->setClass(ComputedValuesItemList::class)
+          ->setSetting('field', 'non_valid_computed_entity_reference')
+          ->setLabel(t('Valid Computed Entity Reference'));
+        break;
+      case 'multiplier':
+        $fields['multiplier'] = BaseFieldDefinition::create('multiplier')
+          ->setLabel(t('Multiplied integer'))
+          ->setSetting('factor', 3);
+        break;
+    }
+  }
+  return $fields;
+}
\ No newline at end of file
diff --git a/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/ComputedValuesItemList.php b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/ComputedValuesItemList.php
new file mode 100644
index 0000000..d24d325
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/ComputedValuesItemList.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Drupal\field_computed_test\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\ComputedFieldItemListBase;
+use Drupal\Core\Field\FieldItemListComputedInterface;
+
+
+class ComputedValuesItemList extends ComputedFieldItemListBase {
+
+  protected function computeFieldItemListValues(){
+    $index = 0;
+    if (!isset($this->list[$index]) || $this->list[$index]->isEmpty()) {
+
+      switch ($this->getSetting('field')) {
+        case 'valid_computed_timestamp':
+          $this->list[$index] = $this->createItem($index, \Drupal::time()->getRequestTime());
+          break;
+        case 'valid_computed_entity_reference':
+          $parent = $this->getEntity();
+          if (!$parent->isNew()) {
+            $this->list[$index] = $this->createItem($index, $parent->id() == 1 ? 2 : 1);
+          }
+          break;
+        case 'non_valid_computed_entity_reference':
+          $parent = $this->getEntity();
+          if (!$parent->isNew()) {
+            $this->list[$index] = $this->createItem($index, 3);
+          }
+          break;
+        case 'non_valid_computed_timestamp':
+          $this->list[$index] = $this->createItem($index, 'A');
+          break;
+        case 'non_valid_computed_entity_reference':
+          $this->list[$index] = $this->createItem($index, 'A');
+          break;
+      }
+    }
+  }
+
+}
diff --git a/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/Multiplier.php b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/Multiplier.php
new file mode 100644
index 0000000..7d24a19
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/Multiplier.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace Drupal\field_computed_test\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\FieldItemBase;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\Core\TypedData\DataDefinition;
+
+/**
+ * @FieldType(
+ *   id = "multiplier",
+ *   label = @Translation("Multiplier"),
+ *   description = @Translation("Computed multiplied integer based on a stored integer."),
+ *   default_widget = "number",
+ *   default_formatter = "number_integer",
+ * )
+ */
+class Multiplier extends FieldItemBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
+
+    $properties['value'] = DataDefinition::create('integer')
+      ->setLabel(t('Original value'));
+    $properties['multipliedValue'] = DataDefinition::create('integer')
+      ->setLabel(t('Multiplied value'))
+      ->setComputed(TRUE)
+      ->setClass(MultiplierProcessor::class);
+    return $properties;
+  }
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function schema(FieldStorageDefinitionInterface $field_definition) {
+    return [
+      'columns' => [
+        'value' => [
+          'type' => 'int',
+        ],
+      ],
+      'indexes' => [
+        'format' => ['value'],
+      ],
+    ];
+  }
+}
\ No newline at end of file
diff --git a/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/MultiplierProcessor.php b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/MultiplierProcessor.php
new file mode 100644
index 0000000..0a20ada
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/MultiplierProcessor.php
@@ -0,0 +1,31 @@
+<?php
+
+
+namespace Drupal\field_computed_test\Plugin\Field\FieldType;
+
+use Drupal\Core\TypedData\TypedData;
+
+class MultiplierProcessor extends TypedData{
+
+  /**
+   * Cached requested time.
+   *
+   * @var integer|null
+   */
+  protected $multipliedValue;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getValue() {
+    if ($this->multipliedValue !== NULL && $this->value !== NULL) {
+      return $this->multipliedValue;
+    }
+    $item = $this->getParent();
+    $factor = $item->getDataDefinition()->getSetting('factor');
+
+    $this->multipliedValue = $item->value * $factor;
+    return $this->multipliedValue;
+  }
+
+}
\ No newline at end of file
diff --git a/core/modules/field/tests/src/Kernel/FieldComputedTest.php b/core/modules/field/tests/src/Kernel/FieldComputedTest.php
new file mode 100644
index 0000000..9211b1c
--- /dev/null
+++ b/core/modules/field/tests/src/Kernel/FieldComputedTest.php
@@ -0,0 +1,175 @@
+<?php
+
+
+namespace Drupal\Tests\field\Kernel;
+
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\KernelTests\KernelTestBase;
+
+
+/**
+ * Test related to computed entity fields.
+ *
+ * @group field
+ */
+class FieldComputedTest extends KernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'system',
+    'field',
+    'text',
+    'user',
+    'entity_test',
+    'field_computed_test',
+  ];
+
+  /**
+   * @var EntityTest[]
+   */
+  public $entities = [];
+
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installSchema('system', ['sequences', 'key_value']);
+    $this->installConfig(['field', 'system']);
+    $this->installEntitySchema('entity_test');
+    $this->installEntitySchema('user');
+
+    $data = $this->getTestDataForEntities($this->getName());
+
+    $this->createTestEntities($data);
+  }
+
+  /**
+   * Test a valid computed 'timestamp' field.
+   */
+  public function testValidComputedTimestamp() {
+    $request_time = \Drupal::time()->getRequestTime();
+    $value = $this->entities[0]->get('valid_computed_timestamp')->value;
+    $this->assertEquals($request_time, $value);
+  }
+
+  /**
+   * Test a valid computed entityreference field.
+   */
+  public function testValidComputedEntityReference() {
+    $referencedEntity = $this->entities[0]->get('valid_computed_entity_reference')->entity;
+    $this->assertInstanceOf(EntityTest::class, $referencedEntity);
+    $this->assertEquals($this->entities[1]->id(), $referencedEntity->id());
+  }
+
+  /**
+   * Test that a non existing entity reference returns NULL.
+   */
+  public function testNonValidComputedEntityReference(){
+    $referencedEntity = $this->entities[0]->get('non_valid_computed_entity_reference')->entity;
+    $this->assertNull($referencedEntity);
+  }
+
+  /**
+   * @expectedException \Drupal\Core\Field\FieldException
+   * @expectedExceptionMessage This value should be a valid number.
+   */
+  public function testNonValidComputedTimestamp() {
+    $data = [
+      [
+        'type' => 'non_valid_computed_timestamp',
+        'title' => 'Entity with a non valid computed timestamp',
+      ],
+    ];
+    $this->createTestEntities($data);
+  }
+
+
+  /**
+   * Test that the processed Multiplier works correctly.
+   */
+  public function testMultiplierFieldType(){
+    $originalValue = 9;
+    $factor = 3;
+    $multipliedValue = $this->entities[0]->get('multiplier')->multipliedValue;
+    $this->assertEquals($originalValue*$factor, $multipliedValue);
+  }
+
+
+
+  /**
+   * Get an array of test data for the creation of entities.
+   *
+   * @param $methodName
+   *
+   * @return array Data for creation of test entities.
+   */
+  private function getTestDataForEntities($methodName){
+    $data = [];
+    switch ($methodName) {
+      case "testValidComputedTimestamp":
+        $data = [
+          [
+            'type' => 'valid_computed_timestamp',
+            'title' => 'Entity with valid computed timestamp',
+          ],
+        ];
+        break;
+      case "testNonValidComputedEntityReference":
+        $data = [
+          [
+            'type' => 'non_valid_computed_entity_reference',
+            'title' => 'Entity A',
+          ],
+          [
+            'type' => 'non_valid_computed_entity_reference',
+            'title' => 'Entity B',
+          ],
+        ];
+        break;
+      case "testValidComputedEntityReference":
+        $data = [
+          [
+            'type' => 'valid_computed_entity_reference',
+            'title' => 'Entity A',
+          ],
+          [
+            'type' => 'valid_computed_entity_reference',
+            'title' => 'Entity B',
+          ],
+        ];
+        break;
+      case "testMultiplierFieldType":
+        $data = [
+          [
+            'type' => 'multiplier',
+            'title' => 'Entity with multiplier field'
+          ],
+        ];
+        break;
+    }
+    return $data;
+  }
+
+  /**
+   * Create some Test Entities based on an array of data.
+   */
+  private function createTestEntities($data) {
+    foreach ($data as $item) {
+      $entity = EntityTest::create([
+        'type' => $item['type'],
+        'title' => $item['title'],
+      ]);
+      if($entity->bundle() == 'multiplier'){
+        $entity->set('multiplier', 9);
+      }
+      $entity->save();
+      $this->entities[] = $entity;
+    }
+  }
+}
\ No newline at end of file
diff --git a/core/modules/views/tests/src/Unit/Plugin/field/FieldTest.php b/core/modules/views/tests/src/Unit/Plugin/field/FieldTest.php
index 2b929f3..1f4bfa4 100644
--- a/core/modules/views/tests/src/Unit/Plugin/field/FieldTest.php
+++ b/core/modules/views/tests/src/Unit/Plugin/field/FieldTest.php
@@ -83,6 +83,13 @@ protected function setUp() {
       ->method('getDefaultFieldSettings')
       ->willReturn([]);
 
+    $typed_data_manager = $this->getMock('Drupal\Component\Plugin\PluginManagerInterface');
+    // @todo: maybe use a reasonable argument
+    $typed_data_manager->expects($this->any())
+      ->method('getDefinition')
+      ->with($this->anything())
+      ->will($this->returnValue(['list_class' => '\Drupal\Core\Field\FieldItemList']));
+
     $this->languageManager = $this->getMock('Drupal\Core\Language\LanguageManagerInterface');
     $this->renderer = $this->getMock('Drupal\Core\Render\RendererInterface');
 
@@ -94,6 +101,7 @@ protected function setUp() {
 
     $this->container = new ContainerBuilder();
     $this->container->set('plugin.manager.field.field_type', $this->fieldTypePluginManager);
+    $this->container->set('typed_data_manager', $typed_data_manager);
     \Drupal::setContainer($this->container);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
index 616f6ba..1f2cab1 100644
--- a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
@@ -64,8 +64,16 @@ protected function setUp() {
       ->with($this->fieldType)
       ->will($this->returnValue($this->fieldTypeDefinition['field_settings']));
 
+    $typed_data_manager = $this->getMock('Drupal\Component\Plugin\PluginManagerInterface');
+    // @todo: maybe use a reasonable argument
+    $typed_data_manager->expects($this->any())
+      ->method('getDefinition')
+      ->with($this->anything())
+      ->will($this->returnValue(['list_class' => '\Drupal\Core\Field\FieldItemList']));
+
     $container = new ContainerBuilder();
     $container->set('plugin.manager.field.field_type', $field_type_manager);
+    $container->set('typed_data_manager', $typed_data_manager);
     \Drupal::setContainer($container);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
index 541ec88..5a511cd 100644
--- a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
@@ -472,9 +472,12 @@ public function testLabel() {
    *   - Fields array for $fields.
    */
   public function providerGet() {
+    $items = $this->getMockBuilder('Drupal\Core\Field\FieldItemList')
+      ->disableOriginalConstructor()
+      ->getMock();
     return [
       // Populated fields array.
-      ['result', 'field_name', 'langcode', ['field_name' => ['langcode' => 'result']]],
+      [$items, 'field_name', 'langcode', ['field_name' => ['langcode' => $items]]],
       // Incomplete fields array.
       ['getTranslatedField_result', 'field_name', 'langcode', ['field_name' => 'no_langcode']],
       // Empty fields array.
diff --git a/core/tests/Drupal/Tests/Core/Entity/TypedData/EntityAdapterUnitTest.php b/core/tests/Drupal/Tests/Core/Entity/TypedData/EntityAdapterUnitTest.php
index 953daac..d5832d7 100644
--- a/core/tests/Drupal/Tests/Core/Entity/TypedData/EntityAdapterUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/TypedData/EntityAdapterUnitTest.php
@@ -141,8 +141,15 @@ protected function setUp() {
     $this->typedDataManager = $this->getMock(TypedDataManagerInterface::class);
     $this->typedDataManager->expects($this->any())
       ->method('getDefinition')
-      ->with('entity')
-      ->will($this->returnValue(['class' => '\Drupal\Core\Entity\Plugin\DataType\EntityAdapter']));
+      ->will($this->returnCallback(function($plugin_id){
+        switch ($plugin_id) {
+          case 'entity':
+            return ['class' => '\Drupal\Core\Entity\Plugin\DataType\EntityAdapter'];
+          default:
+            // @todo: maybe use a reasonable argument value
+            return ['list_class' => '\Drupal\Core\Field\FieldItemList'];
+        }
+      }));
     $this->typedDataManager->expects($this->any())
       ->method('getDefaultConstraints')
       ->willReturn([]);