The last time Mara appeared in a film (appropriately David Fincher's "The Social Network"), she had long, luscious brown hair and a very girl-next-door overall vibe. But no longer. Mara and Fincher open up to Entertainment Weekly in this week's issue and talk about how the prestigious director told his leading lady right up front that she was going to have to change a lot for the role.

"I told Rooney, 'You're going to be emaciated, you have to be naked, you have to get raped [on screen], get pierced, smoke cigarettes, ride a motorcycle,'" Fincher recalled saying. "'I need you to really concentrate and tell me this is something you want.'"

Spoiler alert: it was.

Since, Mara has had her hair chopped off -- "hairstylist Danilo Dixon pulled Mara’s lovely brown hair back into a braid, asked if she was ready, and squeezed the scissors. He handed her the foot-long twist in a Ziploc bag (she still has it)" -- and has received eyebrow, ears and nipple piercings. Surprisingly enough, it wasn't the change in her physical appearance or prospect of revealing all on the big screen that terrified her, but the prospect of riding a motorcycle.

“There were certainly things I was scared to do, but I never thought I wasn't up for the challenge," she said. "The motorcycle was the thing I really didn’t want to do. You know, you're going to be raped, be naked... But as soon as he was like, 'You’re going to have to ride a motorcycle,' I was like, 'Oh, really?'"

Despite the backlash to the fact that Fincher is adapting a novel that already has a beloved Swedish adaptation and that his Lisbeth Salander might be too "weak" (as people criticized the provocative teaser poster that was released earlier this year), Fincher is confident that his film is going to be everything fans want it to be.

"We've got something very simple to deliver on," he said. "A gigantic f---ing book that people have very rigid preconceived notions of, to the point that they actually take umbrage with a teaser poster."

Are you excited to see Fincher's "The Girl with the Dragon Tattoo"? Tell us in the comments section below or on Twitter!