diff --git a/core/lib/Drupal/Core/Entity/ContentEntityBase.php b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
index 3cd9df2..e1ec846 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -158,6 +158,9 @@
   /**
    * Whether to serialize the complete entity structure.
    *
+   * If set to TRUE when the entity is being serialized a deep serialization
+   * will be performed and the flag will be automatically set back to FALSE.
+   *
    * @var bool
    */
   protected $deepSerialization = FALSE;
@@ -470,16 +473,6 @@ public function __sleep() {
   /**
    * {@inheritdoc}
    */
-  public function deepSerialize() {
-    // When running a deep serialization the flag "deepSerialization" has to be
-    // set in order to serialize referenced entities as well.
-    $this->deepSerialization = TRUE;
-    return serialize($this);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function setDeepSerialization($deep_serialization = TRUE) {
     $this->deepSerialization = $deep_serialization;
   }
diff --git a/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php b/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php
index 0de625a..e6ed455 100644
--- a/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php
+++ b/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php
@@ -237,14 +237,6 @@ public function isValidationRequired();
   public function setValidationRequired($required);
 
   /**
-   * Returns a deeply serialized entity.
-   *
-   * @return string
-   *   The deeply serialized entity.
-   */
-  public function deepSerialize();
-
-  /**
    * Flags the entity for deep serialization.
    *
    * After calling this method and serializing the entity e.g.
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/ContentEntitySerializationTest.php b/core/tests/Drupal/KernelTests/Core/Entity/ContentEntitySerializationTest.php
index 7e2a442..4feee94 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/ContentEntitySerializationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/ContentEntitySerializationTest.php
@@ -108,8 +108,10 @@ protected function doTestSerialization($deep_serialization) {
     $entity_level_zero->$field_name->entity->name = 'entity level one';
     $entity_level_zero->$field_name->entity->$field_name->entity->name = 'entity level two';
 
-    $serialized_entity = $deep_serialization ? $entity_level_zero->deepSerialize() : serialize($entity_level_zero);
-    $entity_level_zero = unserialize($serialized_entity);
+    if ($deep_serialization) {
+      $entity_level_zero->setDeepSerialization(TRUE);
+    }
+    $entity_level_zero = unserialize(serialize($entity_level_zero));
 
     // If regular serialization is tested then the changes on the referenced
     // entities should be lost, but kept if deep serialization is tested.