diff --git a/src/Block/FeatureMediaBlockService.php b/src/Block/FeatureMediaBlockService.php
index eccc08ffb..00fd405ff 100644
--- a/src/Block/FeatureMediaBlockService.php
+++ b/src/Block/FeatureMediaBlockService.php
@@ -14,6 +14,7 @@
 namespace Sonata\MediaBundle\Block;
 
 use Sonata\AdminBundle\Admin\AdminInterface;
+use Sonata\AdminBundle\Form\FormMapper as AdminFormMapper;
 use Sonata\AdminBundle\Form\Type\ModelListType;
 use Sonata\BlockBundle\Block\BlockContextInterface;
 use Sonata\BlockBundle\Block\Service\AbstractBlockService;
@@ -27,6 +28,7 @@
 use Sonata\MediaBundle\Model\MediaInterface;
 use Sonata\MediaBundle\Model\MediaManagerInterface;
 use Sonata\MediaBundle\Provider\Pool;
+use Symfony\Component\Form\CallbackTransformer;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\Form\Extension\Core\Type\TextareaType;
 use Symfony\Component\Form\Extension\Core\Type\TextType;
@@ -71,6 +73,10 @@ public function configureSettings(OptionsResolver $resolver): void
 
     public function configureEditForm(FormMapper $form, BlockInterface $block): void
     {
+        if (!$form instanceof AdminFormMapper) {
+            throw new \InvalidArgumentException('Feature media block requires to be used in the Admin context');
+        }
+
         $formatChoices = $this->getFormatChoices($block->getSetting('mediaId'));
 
         $form->add('settings', ImmutableArrayType::class, [
@@ -103,7 +109,7 @@ public function configureEditForm(FormMapper $form, BlockInterface $block): void
                     ],
                     'label' => 'form.label_orientation',
                 ]],
-                [$this->getMediaBuilder(), null, []],
+                [$this->getMediaBuilder($form), null, []],
                 ['format', ChoiceType::class, [
                     'required' => \count($formatChoices) > 0,
                     'choices' => $formatChoices,
@@ -204,7 +210,10 @@ private function getFormatChoices(?MediaInterface $media = null): array
         return $formatChoices;
     }
 
-    private function getMediaBuilder(): FormBuilderInterface
+    /**
+     * @param AdminFormMapper<object> $form
+     */
+    private function getMediaBuilder(AdminFormMapper $form): FormBuilderInterface
     {
         if (null === $this->mediaAdmin) {
             throw new \LogicException('The SonataAdminBundle is required to render the edit form.');
@@ -214,12 +223,20 @@ private function getMediaBuilder(): FormBuilderInterface
             'translation_domain' => 'SonataMediaBundle',
             'edit' => 'list',
         ]);
+        $fieldDescription->setAssociationAdmin($this->mediaAdmin);
 
-        return $this->mediaAdmin->getFormBuilder()->create('mediaId', ModelListType::class, [
+        $formBuilder = $form->getFormBuilder()->create('mediaId', ModelListType::class, [
             'sonata_field_description' => $fieldDescription,
             'class' => $this->mediaAdmin->getClass(),
             'model_manager' => $this->mediaAdmin->getModelManager(),
             'label' => 'form.label_media',
         ]);
+
+        $formBuilder->addModelTransformer(new CallbackTransformer(
+            static fn (?MediaInterface $value): ?MediaInterface => $value,
+            static fn (?MediaInterface $value) => $value instanceof MediaInterface ? $value->getId() : $value
+        ));
+
+        return $formBuilder;
     }
 }
diff --git a/src/Block/GalleryBlockService.php b/src/Block/GalleryBlockService.php
index 45533213f..ca003ccbb 100644
--- a/src/Block/GalleryBlockService.php
+++ b/src/Block/GalleryBlockService.php
@@ -14,6 +14,7 @@
 namespace Sonata\MediaBundle\Block;
 
 use Sonata\AdminBundle\Admin\AdminInterface;
+use Sonata\AdminBundle\Form\FormMapper as AdminFormMapper;
 use Sonata\AdminBundle\Form\Type\ModelListType;
 use Sonata\BlockBundle\Block\BlockContextInterface;
 use Sonata\BlockBundle\Block\Service\AbstractBlockService;
@@ -29,6 +30,7 @@
 use Sonata\MediaBundle\Model\GalleryManagerInterface;
 use Sonata\MediaBundle\Model\MediaInterface;
 use Sonata\MediaBundle\Provider\Pool;
+use Symfony\Component\Form\CallbackTransformer;
 use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\Form\Extension\Core\Type\NumberType;
@@ -74,6 +76,10 @@ public function configureSettings(OptionsResolver $resolver): void
 
     public function configureEditForm(FormMapper $form, BlockInterface $block): void
     {
+        if (!$form instanceof AdminFormMapper) {
+            throw new \InvalidArgumentException('Gallery block requires to be used in the Admin context');
+        }
+
         $contextChoices = [];
 
         foreach ($this->pool->getContexts() as $name => $context) {
@@ -124,7 +130,7 @@ public function configureEditForm(FormMapper $form, BlockInterface $block): void
                     'choices' => $formatChoices,
                     'label' => 'form.label_format',
                 ]],
-                [$this->getGalleryBuilder(), null, []],
+                [$this->getGalleryBuilder($form), null, []],
                 ['pauseTime', NumberType::class, [
                     'label' => 'form.label_pause_time',
                 ]],
@@ -183,7 +189,10 @@ public function validate(ErrorElement $errorElement, BlockInterface $block): voi
     {
     }
 
-    private function getGalleryBuilder(): FormBuilderInterface
+    /**
+     * @param AdminFormMapper<object> $form
+     */
+    private function getGalleryBuilder(AdminFormMapper $form): FormBuilderInterface
     {
         if (null === $this->galleryAdmin) {
             throw new \LogicException('The SonataAdminBundle is required to render the edit form.');
@@ -193,13 +202,21 @@ private function getGalleryBuilder(): FormBuilderInterface
             'translation_domain' => 'SonataMediaBundle',
             'edit' => 'list',
         ]);
+        $fieldDescription->setAssociationAdmin($this->galleryAdmin);
 
-        return $this->galleryAdmin->getFormBuilder()->create('galleryId', ModelListType::class, [
+        $formBuilder = $form->getFormBuilder()->create('galleryId', ModelListType::class, [
             'sonata_field_description' => $fieldDescription,
             'class' => $this->galleryAdmin->getClass(),
             'model_manager' => $this->galleryAdmin->getModelManager(),
             'label' => 'form.label_gallery',
         ]);
+
+        $formBuilder->addModelTransformer(new CallbackTransformer(
+            static fn (?MediaInterface $value): ?MediaInterface => $value,
+            static fn (?MediaInterface $value) => $value instanceof MediaInterface ? $value->getId() : $value
+        ));
+
+        return $formBuilder;
     }
 
     /**
diff --git a/src/Block/MediaBlockService.php b/src/Block/MediaBlockService.php
index fc7ce012a..17e7e47a1 100644
--- a/src/Block/MediaBlockService.php
+++ b/src/Block/MediaBlockService.php
@@ -25,6 +25,7 @@
 use Sonata\BlockBundle\Model\BlockInterface;
 use Sonata\Form\Type\ImmutableArrayType;
 use Sonata\Form\Validator\ErrorElement;
+use Sonata\MediaBundle\Model\GalleryInterface;
 use Sonata\MediaBundle\Model\MediaInterface;
 use Sonata\MediaBundle\Model\MediaManagerInterface;
 use Sonata\MediaBundle\Provider\Pool;
@@ -71,7 +72,7 @@ public function configureSettings(OptionsResolver $resolver): void
     public function configureEditForm(FormMapper $form, BlockInterface $block): void
     {
         if (!$form instanceof AdminFormMapper) {
-            throw new \InvalidArgumentException('Media Block requires to be used in the Admin context');
+            throw new \InvalidArgumentException('Media block requires to be used in the Admin context');
         }
 
         if (!$block->getSetting('mediaId') instanceof MediaInterface) {
@@ -223,8 +224,8 @@ private function getMediaBuilder(AdminFormMapper $form): FormBuilderInterface
         ]);
 
         $formBuilder->addModelTransformer(new CallbackTransformer(
-            static fn (?MediaInterface $value): ?MediaInterface => $value,
-            static fn (?MediaInterface $value) => $value instanceof MediaInterface ? $value->getId() : $value
+            static fn (?GalleryInterface $value): ?GalleryInterface => $value,
+            static fn (?GalleryInterface $value) => $value instanceof GalleryInterface ? $value->getId() : $value
         ));
 
         return $formBuilder;