Oscars Fashion: 'Dragon Tattoo' star Rooney Mara Tells the Story of Her Custom Givenchy Gown

Kevork Djansezian/Getty Images

Nominee Rooney Mara was definitely one of the Oscars' best dressed Sunday. She wore a couture Givenchy made expressly for her.

our editor recommends

Oscar Fashion: Angelina Jolie Flashes Some Leg in a Versace Gown (Poll)

Oscar Fashion: Emma Stone Copies Nicole Kidman's 2007 Red Gown (Poll)

Oscar Fashion: Jessica Chastain Rules the Red Carpet in Alexander McQueen (Poll)

PHOTOS: Oscars 2012 Red Carpet Arrivals

"It was custom designed with Riccardo Tisci for me based an idea that I had," Rooney tells The Hollywood Reporter of the pearl-colored lace mermaid gown, which had a skin-toned satin bra closure in the back. The zipper was also done in natural satin in contrast to the dress.

"They were very generous in letting me give them my input," she continues, "and were the first people to approach me about an Oscar gown."

We're not sure Rooney realizes that Givenchy couture and Riccardo Tisci are about the hottest fashion commodities going right now. Givenchy spring 2012 is one of the most coveted collections of all time. It's already nearly sold out at stores without the pieces even having hit the floor.

PHOTOS: Academy Awards 2012 Complete Winners List

"The fabric is beautiful," she went on about the complicated and very delicate lace of the gown that fell into a lovely and natural train. "It's modern but romantic. That's the combination I like." 

Rooney was, unlike most virgin Oscar-goers, unflappable -- in a way, perhaps, The Girl With the Dragon Tattoo's Lisbeth Salander would be. "It's been a pretty calm week," she confessed.

STORY: Oscars 2012 Winners List

"My whole family is here," she says. "I start making a new film in March, so afterwards, I'll catch my breath and start rehearsing. I've learned so much from the time I got the part till now, but the important part to me is to feel comfortable and like myself -- and this dress is part of the plan."