You've got approximately 472 bras in your underwear drawer, so surely one of those will suffice on your wedding day, right?
Think again, sister. Unless your gown allows you to go al fresco (don't limbo too low, if that's the case), you'll need to give some deep thought to your bridal bra. For example, if your dress features a low back, yet requires support up front, you'll want to invest in a backless, strapless bra that's both comfortable and undetectable through the fabric. For those well-endowed women who have chosen a plunging neckline, a super-low, yet supportive bra will be in order to stay supported and covered. Women with a smaller bust might be able to get away with a set of sturdy pasties.
Since every gown is about as different as every woman's body, it's essential for brides to consult with a lingerie expert. Often, the bridal shop where you purchase your gown has an in-house specialist, or your consultant can recommend a local lingerie boutique where you can be fitted and measured with the stipulations of your gown in mind. Be sure to take along your bra for any and all fittings, as it can significantly impact necessary alterations. Also, take a few hours to test-drive the garment by wearing it around the house. If it's miserably uncomfortable or difficult to dance in, you'll want to take another shopping trip to find a bra with a better fit. There's just no sense in hiring a DJ if you can't wave your hands in air without worrying you'll expose yourself.