After weeks of speculation, countless screen tests and lots of name-dropping, Sony Pictures have confirmed Rooney Mara has secured the role of Lisbeth Salander in David Fincher’s adaptation of The Girl with the Dragon Tattoo.

It seems that Fincher got his wish of casting an unknown over established actresses, such as Natalie Portman, Emily Browning, Ellen Page, Scarlett Johansson and Carey Mulligan, who have all been linked to the role at some stage.

Mara, who agreed to terms when she initially screen-tested for the role, will star alongside Daniel Craig , Robin Wright and Stellan Skarsgaard in the adaptation of Steig Larsson’s acclaimed crime novel, the first installment in the Millennium Trilogy.

The deal reportedly includes an option for the two potential sequels, The Girl Who Played with Fire and The Girl Who Kicked the Hornets’ Nest, that will effectively conclude the Millennium Trilogy, should the first film be the success Sony are hoping for.

Mara will next be seen in Fincher’s The Social Network, a film about the founding of the social networking website Facebook, with a scheduled release date of October 1, 2010.

Sony Pictures previously announced that The Girl with the Dragon Tattoo will hit cinemas on December 21, 2011, with production expected to begin this Autumn, once Fincher’s completes promo duties for The Social Network.

Deadline reported this one.