File this under the "why didn't they think of this sooner?" category. The genius Second Base demi cami slips on beneath any top or dress and adds a comfortable, cleavage-concealing layer without any bulk or bunching. Available in a variety of designs that range from practical for day to glamorous for evening (like this gorgeous lace Celeste), these camis are so light you'll barely know they're there.
$30-$38 at shopsecondbase.com