Symfony 2: how to make firstname and lastname in one column in Symfony2? -

now have firstname , lastname fields, how make firstname , lastname in 1 column in symfony2?

for example:

label = fullname input box = firstname input box + lastname input box error message =  fullname error message, based on firstname , lastname 

like datatime.

read documentation on form theming: http://symfony.com/doc/2.0/cookbook/form/form_customization.html