Not Picking Up If Exist File

[eluser]razerone[/eluser]
I am just trying something new Not picking up file if exist

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

Code:

class Welcome extends CI_Controller {

public function index() {

  if (file_exists(APPPATH . 'views/theme/' . $filename)) {
      $this->load->view('theme/'.$filename);
  }
  else {
      $this->load->view('default/template/common/welcome_message.php');
  }
}
}