diff --git a/src/Normalizer/RelationshipItem.php b/src/Normalizer/RelationshipItem.php
index 90d6dab..b031fad 100644
--- a/src/Normalizer/RelationshipItem.php
+++ b/src/Normalizer/RelationshipItem.php
@@ -99,6 +99,7 @@ class RelationshipItem {
     return [
       $this->targetKey => $this->getTargetEntity()->uuid(),
       'meta' => $this->metadata,
+      'target_key' => $this->targetKey,
     ];
   }
 
diff --git a/src/Normalizer/Value/RelationshipItemNormalizerValue.php b/src/Normalizer/Value/RelationshipItemNormalizerValue.php
index 29d599c..d37ab5c 100644
--- a/src/Normalizer/Value/RelationshipItemNormalizerValue.php
+++ b/src/Normalizer/Value/RelationshipItemNormalizerValue.php
@@ -41,7 +41,7 @@ class RelationshipItemNormalizerValue extends FieldItemNormalizerValue implement
     }
     $rasterizedValue = [
       'type' => $this->resource->getTypeName(),
-      'id' => $value['target_id'],
+      'id' => is_array($value) ? $value[$value['target_key']] : $value,
     ];
 
     if (!empty($value['meta'])) {