Hollywood's Big NightBest of the 2013 Oscars Red Carpet (PHOTOS)Isabel Wilkinson02.24.13Hollywood's Big NightBest of the 2013 Oscars Red Carpet (PHOTOS)Jessica Chastain channels Old Hollywood in Giorgio Armani Privé, while Jennifer Lawrence stuns in Dior Haute Couture. See red carpet highlights on Hollywood's biggest night. Isabel Wilkinson02.24.13 11:45 PM ETGettyJessica Chastain channels Old Hollywood in Giorgio Armani Privé while Reese Witherspoon opts for Louis Vuitton. See highlights from the red carpet on Hollywood's biggest night. Kevin Winter/GettyMichelle ObamaThe audience was shocked when the first lady appeared in the theater by telecast to announce the Best Picture winner, Argo. She wore a beautiful beaded metallic dress by Naeem Khan, and of course her signature bangs were front and center. Jason Merritt/Getty Jennifer LawrenceThe Best Actress winner was a crowd favorite in an ivory, strapless Dior Haute Couture dress with a massive train and a long necklace that ran down her back. Jason Merritt/GettyJessica Chastain Nominated for her role in Zero Dark Thirty, Chastain channeled old-Hollywood glamour in a custom Giorgio Armani strapless copper-toned silk satin gown encrusted with Swarovski crystals and Harry Winston jewels. “It’s a very ‘Happy Birthday, Mr. President’ kind of dress,” she said. “It reminds me of old-Hollywood glamour.” GettyAnne HathawayThe best-supporting-actress winner opted for a Prada light pink duchesse satin backless column dress. “I didn’t know what I was wearing until about three hours ago,” she said. “But this is the one that spoke to me in the end.” She added of her dress: “My mom says it’s business in the front and a party in the back.” Frederic j. BrownLiev Schreiber and Naomi WattsShe's usually in Zac Posen, but Naomi Watts (nominated for her role in The Impossible) changed things up in a structural, glittering one-shoulder dress by Giorgio Armani Privé. Jennifer AnistonAniston looked simple in a red strapless Valentino dress, Fred Leighton jewels, and a red lizard minaudière and strappy satin shoes by Salvatore Ferragamo. “It feels very princess-y,” she said of the dress. “I feel like it’s very King and I.” Jason Merritt/GettyAmanda SeyfriedSeyfreid, who performed in the Les Misérables ensemble during the show, looked stunning a pale Alexander McQueen dress, Roger Vivier shoes, and Lorraine Schwartz jewels. “They’ve been working on this for months,” she said of the dress. “I feel super lucky.” Jason Merritt/GettyAmy AdamsAdams looked regal in a strapless gray tulle dress by Oscar de la Renta. “I worked with Mr. de la Renta on it, and it was just a magical experience,” she said of the dress. Kevork Djansezian/GettyKerry WashingtonWashington—a regular on our best-dressed lists—looked unsurprisingly chic in a strapless coral satin Miu Miu belted gown with a nude tulle bustier enriched with paillettes and Swarovski crystals and a red Prada clutch. Jason Merritt/GettyQuvenzhané WallisWallis wore a blue princess dress by Armani with a rhinestone tiara. She told Ryan Seacrest of the dress: “I liked it because it was sparkling and fluffy.” There was, of course, a “special” dog purse to match. Michael Buckner/GettyCharlize TheronThe actress looked sleek in a white strapless Dior Couture dress and Harry Winston jewels. Jason Merritt/GettyJennifer Garner and Ben AffleckGarner looked chic in a custom strapless purple Gucci dress with a long ruffle down the back, while Argo director Affleck wore head-to-toe Gucci as well. Jason Merritt/GettyGeorge Clooney and Stacey KeiblerKeibler looked stunning a black Naeem Khan dress, Giuseppe Zanotti shoots, Lorraine Schwartz jewels, and a Tiffany & Co. bag. “I sewed most of the sequins on myself,” Clooney joked of his girlfriend’s dress. Frederic J. Brown/GettySally FieldThe best-supporting-actress nominee looked stunning in a bright red Valentino dress with long sleeves. Kevin Winter/GettyBarbra StreisandStreisand, a performer during the show, wore a black Donna Karan Atelier dress that actually had a name: City Lights. The black asymmetrical, bias-cut dress is a waterfall of chiffon layers encrusted with matte gold sequins and beads. Michael Buckner/GettyChristoph WaltzWaltz, who picked up the award for best supporting actor for his role in Django Unchained, wore a midnight blue tuxedo by Prada. Jason Merritt/Getty Reese WitherspoonThe presenter wore a strapless blue Louis Vuitton dress with black detail, Vuitton jewels, and old-Hollywood curls. Frederic J. Brown/Getty (L),Lester Cohen/WireImage (R)Zoe Saldana Saldana opted for ruffles in a white Alexis Mabille Couture strapless dress with appliqué flowers, Neil Lane jewels, Roger Vivier heels, and a Ferragamo clutch. Kevork Djansezian/GettyHalle BerryBerry went angular for the Academy Awards this year with a black Versace dress striped with silver crystals. “Donatella designed this because I said I want to go as a Bond girl to the Oscars, and this is what she came up with.” She paired the dress with a Le Vian Gladiator ring and onyx Adeler earrings.