The one-of-a-kind silk chiffon confection was embellished with organza rosettes, Swarovski crystal rhinestones and silver embroidery.

The first lady accessorized with diamond chandelier earrings, a white gold and diamond ring and a stack of diamond bangles by jeweler Loree Rodkin.

The president summed up his wife's look best before their first dance -- to Beyoncé's rendition of "At Last" -- when he said, "First of all, how good-looking is my wife?"

Michelle Obama has worn Wu once before, during an interview with Barbara Walters. Wu, one of America's leading young designers, debuted his first collection in February 2006 and has since earned accolades such as Fashion Group International's Rising Star Award.