If the glamorous girl on the red carpet in London last night looked unfamiliar, that's because it was Rooney Mara, an actress whose name is becoming synonymous with the art of transformation.
Mara is the American girl charged with bringing the role of Lisbeth Salander in The Girl With The Dragon Tattoo to a fresh big-screen audience. As the millions of fans of Stieg Larsson's books will know, this is not a role for the faint-hearted - including scenes of brutal beatings, rapes, torture, as well as physical transformation into the pale, pierced and tattooed heroine of the story.
Although Mara has appeared in a series of films - including and Tanner Hall (2009) and Nightmare on Elm Street (remake, 2010) - it was as Mark Zuckerberg's spiky girlfriend Erica Albright in The Social Network that she really captured the attention.
It was only her attitude that was spiky though. With her gleaming hair and preppy outfits, she fitted seamlessly into the Harvard set that Zuckerberg, in the film, was so scathing and envious about in equal measure, until she unceremoniously dumped him and inspired him to create Facebook.
Nothing could have prepared her fans for her complete transformation into Lisbeth Salander.
If there are any readers who doubt that she would be able to pull off the role like Swedish actress Noomi Rapace had done before her, she will silence them when the film goes on release later this week.
For the role of the intelligent, traumatised outsider of the film's title, Mara got out of bed at 4:30am every morning to have her body covered in the requisite tattoos. Her hair was dyed as well as her eyebrows, and fake piercings were applied all over her face.
But one thing proved too hard to fake. So Mara proved her commitment even further, heading off to a salon and having her nipple pierced, for the film, for real - surely an Oscar-worthy action in itself.
And last night, she transformed again, this time into a stunning Hollywood icon, suitably attired for the red carpet and any future A-list events that will surely require her presence once awards season begins.
SLIDESHOW: Rooney Mara's changing image...