diff --git a/src/Unirest/File.php b/src/Unirest/File.php
index 4ea2dbd..7db8182 100644
--- a/src/Unirest/File.php
+++ b/src/Unirest/File.php
@@ -14,7 +14,7 @@ class File
     public static function add($filename, $mimetype = '', $postname = '')
     {
         if (function_exists('curl_file_create')) {
-            return curl_file_create($filename, $mimetype = '', $postname = '');
+            return curl_file_create($filename, $mimetype, $postname);
         } else {
             return sprintf('@%s;filename=%s;type=%s', $filename, $postname ?: basename($filename), $mimetype);
         }