Move genesis_header from functions.php to header.php

[Erhnam]

I'm using the genesis_header function to generate my own customer header. It's currently located in the functions.php (see below).

Question; Is there a way to move this function to a seperate file (header.php)? I want to have a better overview of my functions.php because the custom genesis_header contains many code.

add_action( 'genesis_header', 'add_genesis_header' );
function add_genesis_header() {
<code>
}