Halter dresses and backless gowns can be worn with either a bra that has convertible straps that wrap over the shoulders and around the waist or self-adhering "stay cups," which are fixed to the body without straps. Another alternative is to have bra cups sewn into the dress by the seamstress who alters your gown. An Empire gown is the most comfortable and forgiving silhouette, and it doesn't require a waist-nipping foundation underneath. You can wear just about any undergarment, including a standard bra, bustier, or bodysuit. A sheath dress that fits closely against the body requires a smooth, unembellished undergarment. The best choices: a seamless bra or a bodysuit. For more shaping and support, select a stretch bodydress that acts as both a slip and a bodysuit.

Three-Way Bras
This bra (above) has three straps -- two short, one long -- to fit a variety of bridal-gown styles. The two short straps can be crossed in back, or the bra can be worn strapless. For a backless gown, the two short straps attach conventionally, while the long one wraps around the waist to prevent it from riding up and to keep it hidden. For a halter back, a short strap is fastened around the neck and the long strap around the waist.

Bodysuits
Derived from the leotard, a bodysuit is a comfortable, flexible one-piece garment. It may be made from nylon or spandex to hold in the tummy, or may come with underwire cups to lift the bust. A sheer, seamless bodysuit is ideal for a dress made of lightweight material.