diff --git a/Form/DataTransformer/PhoneNumberToArrayTransformer.php b/Form/DataTransformer/PhoneNumberToArrayTransformer.php
index 89d2b0a3..81b2cc7b 100644
--- a/Form/DataTransformer/PhoneNumberToArrayTransformer.php
+++ b/Form/DataTransformer/PhoneNumberToArrayTransformer.php
@@ -74,7 +74,7 @@ public function reverseTransform($value)
             throw new TransformationFailedException('Expected an array.');
         }
 
-        if ('' === trim(implode('', $value))) {
+        if ('' === trim($value['number'])) {
             return null;
         }
 
diff --git a/Tests/Form/DataTransformer/PhoneNumberToArrayTransformerTest.php b/Tests/Form/DataTransformer/PhoneNumberToArrayTransformerTest.php
index 905b00b9..90d1681a 100644
--- a/Tests/Form/DataTransformer/PhoneNumberToArrayTransformerTest.php
+++ b/Tests/Form/DataTransformer/PhoneNumberToArrayTransformerTest.php
@@ -153,6 +153,11 @@ public function reverseTransformProvider()
                 array('country' => '', 'number' => ''),
                 null,
             ),
+            array(
+                array('GB'),
+                array('country' => 'GB', 'number' => ''),
+                null,
+            ),
             array(
                 array('GB'),
                 array('country' => '', 'number' => 'foo'),