diff --git a/system/DataCaster/DataCaster.php b/system/DataCaster/DataCaster.php
index 854a0b50b32c..29de3987faa9 100644
--- a/system/DataCaster/DataCaster.php
+++ b/system/DataCaster/DataCaster.php
@@ -159,7 +159,7 @@ public function castAs(mixed $value, string $field, string $method = 'get'): mix
             $params = array_map('trim', explode(',', $matches[2]));
         }
 
-        if ($isNullable) {
+        if ($isNullable && ! $this->strict) {
             $params[] = 'nullable';
         }
 
diff --git a/tests/_support/Models/UserCastsTimestampModel.php b/tests/_support/Models/UserCastsTimestampModel.php
index c19353f01319..30f6b3e6b6f7 100644
--- a/tests/_support/Models/UserCastsTimestampModel.php
+++ b/tests/_support/Models/UserCastsTimestampModel.php
@@ -28,8 +28,8 @@ class UserCastsTimestampModel extends Model
         'id'         => 'int',
         'name'       => 'base64',
         'email'      => 'json-array',
-        'created_at' => 'datetime',
-        'updated_at' => 'datetime',
+        'created_at' => '?datetime',
+        'updated_at' => '?datetime',
     ];
     protected array $castHandlers = [
         'base64' => CastBase64::class,