diff --git a/core/lib/Drupal/Core/Field/FieldItemListComputed.php b/core/lib/Drupal/Core/Field/FieldItemListComputed.php
new file mode 100644
index 0000000..b00dc30
--- /dev/null
+++ b/core/lib/Drupal/Core/Field/FieldItemListComputed.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\Core\Field;
+
+use Drupal\Core\Form\FormStateInterface;
+
+abstract class FieldItemListComputed extends FieldItemList implements FieldItemListComputedInterface {
+  /**
+   * Numerically indexed array of field items.
+   *
+   * @var \Drupal\Core\Field\FieldItemInterface[]
+   */
+  protected $list = array();
+
+  /**
+   * {@inheritdoc}
+   */
+  public function computeItems() {
+    $this->list = [];
+    $values = $this->computeItemValues();
+    if (is_array($values) && !empty($values)) {
+      foreach ($values AS $delta => $value) {
+        $this->list[] = $this->createItem($delta, $value);
+      }
+    }
+  }
+
+  /**
+   * This should compute the values that are used to create the field items.
+   *
+   * @return array The values for the field items.
+   */
+  protected abstract function computeItemValues();
+
+  /**
+   * This will do nothing as computed lists are readonly bz default.
+   */
+  public function setValue($values, $notify = TRUE) {}
+
+  /**
+   * This will do nothing as computed lists are readonly bz default.
+   */
+  public function appendItem($value = NULL) {}
+
+  /**
+   * This will do nothing as computed lists are readonly bz default.
+   */
+  public function defaultValuesForm(array &$form, FormStateInterface $form_state) {}
+
+  /**
+   * This will do nothing as computed lists are readonly bz default.
+   */
+  public function removeItem($index) {}
+
+  /**
+   * This will do nothing as computed lists are readonly bz default.
+   */
+  public function set($index, $value) {}
+}
diff --git a/core/lib/Drupal/Core/Field/FieldItemListComputedInterface.php b/core/lib/Drupal/Core/Field/FieldItemListComputedInterface.php
new file mode 100644
index 0000000..f6a6769
--- /dev/null
+++ b/core/lib/Drupal/Core/Field/FieldItemListComputedInterface.php
@@ -0,0 +1,9 @@
+<?php
+namespace Drupal\Core\Field;
+
+interface FieldItemListComputedInterface {
+  /**
+   * This will populate the field item list with computed values.
+   */
+  public function computeItems();
+}
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
index 2a868db..003cd57 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
@@ -102,10 +102,7 @@ public function get($index) {
     if (!is_numeric($index)) {
       throw new \InvalidArgumentException('Unable to get a value with a non-numeric delta in a list.');
     }
-    // Automatically create the first item for computed fields.
-    if ($index == 0 && !isset($this->list[0]) && $this->definition->isComputed()) {
-      $this->list[0] = $this->createItem(0);
-    }
+
     return isset($this->list[$index]) ? $this->list[$index] : NULL;
   }
 
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataManager.php b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
index 7fe362e..552098d 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataManager.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -12,6 +12,7 @@
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Field\FieldItemListComputed;
 use Drupal\Core\Plugin\DefaultPluginManager;
 use Drupal\Core\TypedData\Validation\MetadataFactory;
 use Drupal\Core\Validation\ConstraintManager;
@@ -309,6 +310,9 @@ public function getPropertyInstance(TypedDataInterface $object, $property_name,
     $property->setContext($property_name, $object);
     if (isset($value)) {
       $property->setValue($value, FALSE);
+    } elseif ($property instanceof FieldItemListComputed) {
+      // populate the computed list with values as there are no initial values to set.
+      $property->computeItems();
     }
     return $property;
   }
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..941cdfe
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/field_computed_test.module
@@ -0,0 +1,37 @@
+<?php
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+
+function field_computed_test_entity_base_field_info(EntityTypeInterface $entity) {
+  if ($entity->id() === 'node') {
+    $fields = array();
+
+    $fields['field_dice_count'] = BaseFieldDefinition::create('integer')
+      ->setCustomStorage(false)
+      ->setLabel(t('Dice count'))
+      ->setDisplayOptions('view', array(
+        'label' => 'inline',
+        'type' => 'text_textfield',
+        'weight' => 0,
+      ))
+      ->setDisplayOptions('form', array(
+        'type' => 'integer',
+        'weight' => 10,
+      ))
+      ->setDisplayConfigurable('form', TRUE);
+
+    $fields['field_dice_result'] = BaseFieldDefinition::create('integer')
+      ->setLabel(t('Dice result'))
+      ->setComputed(TRUE)
+      ->setClass('\Drupal\field_computed_test\Plugin\Field\FieldType\DiceFieldItemList')
+      ->setDisplayOptions('view', array(
+        'label' => 'inline',
+        'type' => 'number_integer',
+        'weight' => 0,
+      ));
+
+    return $fields;
+  }
+
+}
diff --git a/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/DiceFieldItemList.php b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/DiceFieldItemList.php
new file mode 100644
index 0000000..06a125d
--- /dev/null
+++ b/core/modules/field/tests/modules/field_computed_test/src/Plugin/Field/FieldType/DiceFieldItemList.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Drupal\field_computed_test\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\FieldItemListComputed;
+
+/**
+ * Represents a configurable dice result.
+ */
+class DiceFieldItemList extends FieldItemListComputed {
+  /**
+   * {@inheritdoc}
+   */
+  protected function computeItemValues() {
+    $items_count = $this->getParent()->getValue()->field_dice_count->value;
+    $values = [];
+    foreach (range(0, $items_count - 1) as $delta) {
+      $values[$delta] = rand(1, 6);
+    }
+    return $values;
+  }
+}