Adding new fields on the same row

Hello,

How can I add 2 new fields on the same row? Now They are on 2.

add_filter('woocommerce_checkout_fields','reorder_woo_fields');

    function reorder_woo_fields($fields) {
     $fields2['billing']['billing_ico'] = array(
        'label'     => __('ICO', 'woocommerce'),
    'placeholder'   => _x('ICO', 'placeholder', 'woocommerce'),
    'required'  => false,
    'class'     => array('form-row-first'),
    'clear'     => true
     );
        	$fields2['billing']['billing_dic'] = array(
        'label'     => __('DIC', 'woocommerce'),
    'placeholder'   => _x('DIC', 'placeholder', 'woocommerce'),
    'required'  => false,
    'class'     => array('form-row-last'),
    'clear'     => true
     );   

            return $fields2;
    }

Cheers.

https://wordpress.org/plugins/woocommerce/