The director revealed that he and Mara worked hard to accomplish the actress's appearance as Lisbeth Salander in the film.
"Rooney's a beautiful girl," Fincher told Entertainment Weekly. "She can look like Audrey Hepburn - but she can also look like a boy.
"So we'd decide where we wanted to put the stud through her eyebrow by asking, 'Where is it going to be most in the way? Where is the most distracting place?' We had to be really sure that the nipple piercing was in the place where it was going to catch the light."
Mara explained in a recent interview that there are "so many different things" that she loves about the character of Lisbeth Salander.
She recently admitted that she has trouble watching her own performances, saying that she is never satisfied with her work.