Ian McKellen to Play Sherlock Holmes in Bill Condon's 'A Slight Trick of the Mind'

As the Toronto International Film Festival kicks off today, much of the attention will be on the diverse slate of films making, in some cases, their worldwide debut. But as is always the case at these events, there are also deals being struck behind the scenes, and a new one will have Sir Ian McKellen playing a retired Sherlock Holmes in an adaptation of Mitch Cullin's A Slight Trick of the Mind.

McKellen will reteam with his Gods and Monsters director Bill Condon on the film, which features a script by The Duchess writer Jeffrey Hatcher. The story takes place in 1947 and follows an aging, mentally waning Holmes as he's haunted by an unsolved case from fifty years earlier. This will obviously be a very different Holmes than we've been seeing of late, as portrayed by Robert Downey Jr., Condon's The Fifth Estate star Benedict Cumberbatch, and Jonny Lee Miller.  There's also a role for Holmes' housekeeper and her son, who happens to be an amateur detective and will probably take on a Watson-esque role.

McKellen will be keeping busy as Gandalf in The Hobbit: The Desolation of Smaug, and as Magneto in X-men: Days of Future Past. Filming on A Slight Trick of the Mind will kick off next April.