The Notebook star was recently reported to have been tapped for a role in the Marvel film adaptation, and although MCAdams admits the rumours are true, she insists a deal is far from done.

She tells the Los Angeles Times, "It's still super-early days, and I don't know where that's gonna go, if it's gonna go anywhere at all."

Further details about the part MCAdams is in negotiations for have yet to be revealed, but if she does sign on, she will star alongside Tilda Swinton and Chiwetel Ejiofor, who has been cast as the villain, Baron Mordo.

Cumberbatch will portray the titular neurosurgeon-turned-sorcerer in director Scott Derrickson's 2016 blockbuster.

MCAdams, who notes she is not a "comic book snob", was previously considered to play Pepper Potts in 2008's Iron Man, but the role went to Gwyneth Paltrow.

The 36 year old later worked with Iron Man Robert Downey, Jr. in the Sherlock Holmes franchise, for which she will allegedly reprise her Irene Adler character for a planned third instalment.