diff --git a/src/Elasticsearch/Serializer/ItemNormalizer.php b/src/Elasticsearch/Serializer/ItemNormalizer.php
index cad183402f3..9b49a40ab73 100644
--- a/src/Elasticsearch/Serializer/ItemNormalizer.php
+++ b/src/Elasticsearch/Serializer/ItemNormalizer.php
@@ -84,7 +84,7 @@ public function supportsDenormalization($data, $type, $format = null, array $con
     /**
      * {@inheritdoc}
      */
-    public function normalize($object, $format = null, array $context = []): array
+    public function normalize($object, $format = null, array $context = [])
     {
         return $this->decorated->normalize($object, $format, $context);
     }
diff --git a/tests/Elasticsearch/Serializer/ItemNormalizerTest.php b/tests/Elasticsearch/Serializer/ItemNormalizerTest.php
index 57982f8f8b2..d4d8429c652 100644
--- a/tests/Elasticsearch/Serializer/ItemNormalizerTest.php
+++ b/tests/Elasticsearch/Serializer/ItemNormalizerTest.php
@@ -83,6 +83,13 @@ public function testNormalize(): void
         self::assertSame(['foo'], $this->itemNormalizer->normalize($object, 'json', ['groups' => 'foo']));
     }
 
+    public function testNormalizeToString(): void
+    {
+        $this->normalizerProphecy->normalize($object = (object) ['foo'], 'json', ['groups' => 'foo'])->willReturn('/foo/iri')->shouldBeCalledOnce();
+
+        self::assertSame('/foo/iri', $this->itemNormalizer->normalize($object, 'json', ['groups' => 'foo']));
+    }
+
     public function testSupportsNormalization(): void
     {
         $this->normalizerProphecy->supportsNormalization($object = (object) ['foo'], 'json')->willReturn(true)->shouldBeCalledOnce();