This year's Met Gala attendees gave us good reason to think two outfits are better than one. And who can blame Ashley Greene  for trading her dramatic Marchesa gown for something a little shorter come afterparty? Those iconic Met stairs (read: not ornate-dress friendly) alone could prompt an outfit change, but we think it gives this A-list set another chance to show off one more great look before night's end. Case in point: Allison Williams's surprising dark and sexy twofer, courtesy of Altuzarra. Or how about Madonna 's Givenchy Haute Couture tartan and fishnets getup that turned into just fishnets all over? The beauty of seeing fashion's finest is actually seeing them at their finest, and that means outfit changes galore. Which stars were bona fide Met Gala quick-change artists? Find out right this way.
Ashley Greene  chose a black-and-gold strapless Marchesa ball gown , which proved a dramatic red carpet choice. Once the afterparty festivities hit, the actress opted to wear a pink printed cocktail dress with platform nude pumps — quite the departure from earlier.
Anne Hathaway  went old-school in her sheer black beaded vintage Valentino  on the red carpet but kept it much shorter (but just as sheer) for the afterparty.
Sienna Miller  topped her white gown with a studded biker jacket  and a box clutch, all by Burberry (of course). Then, keeping within the Brit-punk spirit, she slipped into something more casual — Union Jack intact — for later.
Madonna  picked a Givenchy Haute Couture by Riccardo Tisci look  that combined tartan, shredded fishnets, black leather, chains, and plenty of studs. As for the afterparty? She skipped the tartan topper and kept it very revealing.
Amanda Seyfried  was Givenchy loyal on Met Gala night. On the red carpet, she wore a printed chiffon gown  from the label's Couture Spring '07 collection, and at the afterparty, she slipped into an oversize printed t-shirt (made into a minidress) and rocked black-and-white sandals and a Givenchy Rottweiler clutch.
Allison Williams was full of styling surprises. First, she hit the Met Gala red carpet in a supersexy (sheer, lace, the works) gown by Joseph Altuzarra , only to slip into something equally dark and sexy from the designer, revealing her Saint Laurent pumps, come the afterparty.
Cara Delevingne's studded plunging column dress , white studded clutch, and shoes — all by Burberry — provided the punk early on. But to keep her signature cool-girl style front and center, the British model slipped into a bright blue printed pantsuit, which revealed a lacy bra, too.
Mad Men's Jessica Paré went from purple Jason Wu  to a custom blue-and-black one-shouldered minidress, also by Jason Wu.
Game of Thrones' Emilia Clarke went slightly punk in a red strapless Ralph Lauren gown  and a single Fred Leighton cross earring on the red carpet. But as you can see, the actress went with something darker and without a sweetheart neckline after the main event.
Karen Elson ditched her gold beaded and fringed Julien MacDonald  halter gown in favor of a sexier Saint Laurent LBD, T-strap heels (also by Saint Laurent), and fishnet tights.
Rita Ora chose a fresh white cutout Thakoon gown  for the main event, then spiced things up with something altogether different later in the evening. Her Emilio Pucci Spring '13 gold-embroidered jumpsuit certainly fit the bill of afterparty couture.
Bee Shaffer went with a sweeping pink embroidered Christian Dior fishtail gown  at the Met Gala but kept it cocktail-length for everything that came after. We love that she added a tougher leather jacket, a very evening-appropriate touch.