call one of the method from another class

[eluser]Uresh Patel[/eluser]
Respected,

I have two controllers.I want to call one of the method from one class.
Below both class are different controller files
E.g:

Code:

class User extends CI_Controller {

             function index(){
                 //code
             }

              function list(){
                   //i want to call class 'Blog.Add' method....
             }
}


  class Blog extends CI_Controller {

         function index(){
            //code
         }

         function Add(){
              //code
         }
}

Please suggest good way to do so ....