diff --git a/src/Casts/DateTimeInterfaceCast.php b/src/Casts/DateTimeInterfaceCast.php
index 9230c8b3..3aa75ce5 100644
--- a/src/Casts/DateTimeInterfaceCast.php
+++ b/src/Casts/DateTimeInterfaceCast.php
@@ -39,9 +39,9 @@ protected function castValue(
         }
 
         // Truncate nanoseconds to microseconds (first 6 digits)
-        // Input: 2024-12-02T16:20:15.969827247Z
-        $value = preg_replace('/\.(\d{6})\d*Z$/', '.$1Z', $value);
-        // Output: 2024-12-02T16:20:15.969827Z
+        if (is_string($value)) {
+            $value = preg_replace('/\.(\d{6})\d*Z$/', '.$1Z', $value);
+        }
 
         /** @var DateTimeInterface|null $datetime */
         $datetime = $formats
diff --git a/tests/Casts/DateTimeInterfaceCastTest.php b/tests/Casts/DateTimeInterfaceCastTest.php
index 9c4b2a75..5d4a0f60 100644
--- a/tests/Casts/DateTimeInterfaceCastTest.php
+++ b/tests/Casts/DateTimeInterfaceCastTest.php
@@ -23,7 +23,6 @@
         public DateTimeImmutable $dateTimeImmutable;
     };
 
-
     expect(
         $caster->cast(
             FakeDataStructureFactory::property($class, 'carbon'),