What should I wear to match her dress?

My friend is wearing a black dress: Karen Millen One Shoulder Beaded Dress Black DM029 [DM029] - ｣82 - discount karen millen dresses UK , im going to wear a black tie, but what color shirt and pants should I wear to match her dress? I know its a stupid question, but thanks. Btw, Its for a highschool dance. Thanks alott!!