This would depend completely on the type of bodysuit and dress you have decided to wear. Different bodysuits cover different percentages of our body. 1.If you are wearing an underbust bodysuit, then choose a bra that would complement your dress. 2.In case you are wearing a body control suit that covers not only the waist but also the upper bust, then you would not need to wear a bra at all. 3.A corset shaped bodysuit can come with a bra or just a separate corset. In this case, again choose a bra that would complement the outfit you have chosen to wear.