The 36-year-old Canadian actress revealed as much to The Wrap at the Toronto International Film Festival on Monday. McAdams attended the premiere of her new film, Every Thing Will Be Fine, on Friday.
The news sparked rumors the actress will portray the sorceress Clea, the traditional love interest of Doctor Strange (Cumberbatch). In the Marvel comics, the character teams with Strange to battle both her mother, Umar, and uncle, Dormammu, in the Dark Dimension.
Doctor Strange will be directed by Scott Derrickson, and opens in theaters Nov. 4, 2016. The movie follows the titular character, aka Dr. Stephen Strange, as he defends Earth from magical and mystical threats as the Sorcerer Supreme.
McAdams is best known for The Notebook, and recently starred on True Detective season 2. She last appeared in Southpaw with Jake Gyllenhaal, and is scheduled for Spotlight with Mark Ruffalo and Sherlock Holmes 3 with Robert Downey, Jr.