Red Carpet Arrivals

"It's Vivienne Westwood," Bridesmaids star Rose Byrne said of her slinky, sequined one-shoulder gown. The actress, who presented the Oscar for Best Documentary Film, accessorized the backless design with colorful Chanel earrings, Jimmy Choo heels.

Rooney Mara celebrated her Best Leading Actress nod in a crisp white Givenchy gown with a plunging neckline. "I only just picked it this morning," the Girl With the Dragon Tattoo star said of her Oscars look.

"I just fell in love with this dress. It's clean and elegant," Milla Jovovich said of her sequin Elie Saab Couture gown. The first-time presenter accessorized her silver design with Jacob & Co. jewels and an Edie Parker box clutch.

Kristen Wiig, who is nominated for her Bridesmaids script, chose a nude tulle strapless gown with woven bodice and hand pleated layered skirt by J. Mendel. Neil Lane jewelry, a Judith Leiber clutch and a dark manicure accessorized her look.

Best Actress nominee Michelle Williams chose a silk and organza Louis Vuitton dress with a peplum waist for her big night, and she had to pool her friends to clarify the hue. "I've been asking everyone what color it is, and they say it's coral or maybe pomegranate," she said. (The label officially called it "burnt orange.") The My Week With Marilyn star played up her design with a Fred Leighton for Forevermark necklace that featured 30 carats worth of brilliant-cut diamonds, the jeweler's vintage brooch and a pink Bottega Veneta clutch.

Actress Gwyneth Paltrow wowed in white. She accessorized her Tom Ford gown and dramatic floor length cape with an Anna Hu Haute Joaillerie diamond cuff and ring, Jimmy Choo shoes and a sleek low ponytail.

"I love when they say, 'Who are you wearing?,'" Best Leading Actor nominee George Clooney said, jokingly, on the red carpet. Clooney wore a Giorgio Armani suit for the event, while his girlfriend, Stacy Keibler, chose a champagne-hued, off-the-shoulder Marchesa gown, which she paired with a Judith Leiber clutch and Lorraine Schwartz jewelry.

Best Supporting Actress nominee Jessica Chastain walked the red carpet in a black Alexander McQueen gown with an intricate gold overlay and a flowing chiffon train. She finished her look with $2 million of Harry Winston yellow diamond jewels.

Vera Wang designed Best Actress nominee Viola Davis's strapless green gown, which featured a pleated skirt detail and embroidered neckline. "She did right by me," The Help star graciously said of the designer. She accessorized with matching emerald earrings, a silver box clutch, and a sparkling diamond cuff.

Best Actor nominee Brad Pitt wore a sleek Tom Ford suit to escort his longtime partner Angelina Jolie, who wowed on the red carpet in a velvet Atelier Versace design with a sexy slit. The Oscar presenter completed her look with Neil Lane jewels, a Jaime Mascaro bag and custom Salvatore Ferragamo velvet pumps.

Last year's Best Actress winner Natalie Portman looked sweet in a cherry red Christian Dior dress with polka-dot detailing. She finished the look with a black Charlotte Olympia clutch and Harry Winston diamonds.

Modern Family's Sarah Hyland stepped out in a flowing lavender Alberta Ferretti gown paired with Casadei pumps, diamond Neil Lane chandeliers and a loose chignon.

Presenter Jennifer Lopez posed in a long sleeve Zuhair Murad gown. The American Idol judge accessorized her look with Lorraine Schwartz jewels, Salvatore Ferragamo clutch and Jimmy Choo shoes.

Cameron Diaz took a feminine turn on the red carpet in a pastel Gucci mermaid gown. More than $800,000 worth of Tiffany & Co. diamonds amped up the pretty look.

"I really wanted something that was '30s-inspired," Penelope Ann Miller said of her embellished halter neck Badgley Mischka gown. "I tried to add a modern twist with the headband." The actress accessorized with a Christian Louboutin clutch, and a rare pink diamond ring by Blue Nile.

Sandra Bullock turned heads in a dramatic black and white Marchesa design and added the label's jeweled minaudiere, tiered danglers, a floral cocktail ring and Casadei pumps.

Oscar presenter Emma Stone complemented her strawberry strands with a scarlet Giambattista Valli dress and Louis Vuitton rubies and the label's jeweled minaudiere.

For her 17th (!) Oscar nomination, Meryl Streep went for the gold in Lanvin’s first ever custom-made earth-friendly gown, made from eco-certified fabric sourced with help from Livia Firth’s Green Carpet Challenge. Lizard Salvatore Ferragamo peep-toes, jewels by Fred Leighton and a Lavin bag complete her look.

Best Supporting Actress nominee Octavia Spencer stunned on the Oscar red carpet in a creamy, crystal-embellished Tadashi Shoji gown that she accessorized with Jimmy Choo shoes, Neil Lane jewels and a silver Judith Leiber clutch.

Best Supporting Actress nominee Berenice Bejo wore a mint green Elie Saab gown, which she complemented with Chopard emeralds, a seafoam Swarvoski clutch, Jimmy Choo heels and a braided up-do.

Bridesmaids star Melissa McCarthy chose a custom Marina Rinaldi gown and jewels from Chopard. The Best Supporting Actress nominee accessorized her look with and a clutch and customized shoes from her "best friend from high school," Brian Atwood. "[The message on the sole] said, 'To my best friend, plus Oscars and the date,'" McCarthy said. "It made me cry."

Penelope Cruz’s off-the-shoulder organza gown was custom-made Armani Prive. “I know what I like; I know what I don’t,” she said. Cruz chose Chopard jewels to complete her look.

Oscar presenter Tina Fey made an entrance in a strapless Carolina Herrera peplum gown, a black Roger Vivier clutch and Stuart Weitzman pumps. Bulgari danglers offset her voluminous updo.

“I love this dress because it’s so different and it’s so incredibly me,” Shailene Woodley said of her long-sleeve white Valentino Couture gown. “I’m obsessed with it.” The actress, who starred in the Best Picture nominated film The Descendants, completed her look with diamond drop earrings and a garnet and diamond ring by Harry Winston.

Live! With Kelly host Kelly Ripa posted a video on YouTube of her deciding between two gowns. "I'm down to my final two choices: this lovely celery colored, pale pistachio Carolina Herrera dress which I feel very good in," she said. "It's very comfortable." She completed her look with Fred Leighton jewels and a Judith Leiber clutch.

Ellie Kemper stepped out of The Office and onto the red carpet in a strapless Armani Prive design that she paired with gold Lorraine Schwartz jewelry and a sparkling Salvatore Ferragamo clutch. Of her column's earthy hue, the Bridesmaids actress decided, "Rust sounds too dull, it's glittery rust."

The Descendants actress Judy Greer posed on the red carpet in a sleek Monique Lhuillier column. She finished her look with loose waves, a metallic box clutch by Judith Leiber and Stuart Weitzman heels.

Leslie Mann flaunted her figure in a sequin Roberto Cavalli dress. She set off her vibrant gown, which she simply described as "tight," with complementary blue jewels and a satin Judith Leiber clutch.

The Artist actress Missi Pyle's organic silk and recycled polyester gown was designed by Valentina Delfino, the winner of the third annual Red Carpet Green Dress contest. Chopard diamonds and a Swarovski roll clutch added sparkle to the design.

Busy Philipps cheered on her longtime friend Michelle Williams in a gathered lace Dolce & Gabbana column that she paired with hot pink Brian Atwood heels and edgy Irene Neuwirth danglers and a bangle.

Oscar presenter Maya Rudolph attended the Academy Awards in a plum Johanna Johnson design embellished with crystal cap sleeves and cinched at the waist with a matching silver belt, Neil Lane diamonds and Casadei heels.

Last year's Best Supporting Actress winner for The Fighter, Melissa Leo arrived for the 2012 ceremony in a black and gold colorblock design that she paired with deco accessories including a sparkling clutch and twisted Jimmy Choo sandals.

Albert Nobbs actress Glenn Close swapped her standard black for an emerald-green Zac Posen dress with train and matching tuxedo jacket. She accessorized with Bulgari diamond earrings and a Judith Leiber clutch.

Bridesmaids actress and presenter Wendi McLendon-Covey chose a lace and tulle CB Haute Couture gown and Simon G jewels. She finished her look with a Christian Louboutin clutch and shoes.

American Horror Story actress Kate Mara walked the red carpet in a strapless embellished Jack Guisso Couture gown with Lorraine Schwartz jewels, Brian Atwood shoes and a loose chignon.

Janet McTeer, who scored a Best Supporting Actress nomination for her role in Albert Nobbs, walked the red carpet in a custom draped garnet stretch chiffon gown by David Meister Signature and Piaget jewels.