Using add_rewrite_rule() to redirect to Front Page

Found the solution in this thread:
How to prevent the default home rewrite to a static page

Just disable canonical redirect for front page:

function disable_canonical_redirect_for_front_page( $redirect ) {
    if ( is_page() && $front_page = get_option( 'page_on_front' ) ) {
        if ( is_page( $front_page ) )
            $redirect = false;
    }

    return $redirect;
}
add_filter( 'redirect_canonical', 'disable_canonical_redirect_for_front_page' );