Ian McKellan

Oscar-winning writer-director Bill Condon brings "The Fifth Estate," his film about WikiLeaks founder Julian Assange, to TIFF tonight, but a new collaboration with Ian McKellen is in the works

McKellen has been tapped to star as Sherlock Holmes in Condon's adaptation of the 2005 novel "A Slight Trick of the Mind" by Mitch Cullin, which is set in 1947 and imagines a much older, retired Holmes. "The Duchess" screenwriter Jeffrey Hatcher will write the film. 

This is Condon and McKellen's first collaboration since 1998's "Gods and Monsters," which nabbed Condon a best adapted screenplay Oscar and a nomination for lead actor McKellen.

Condon's current film "The Fifth Estate" stars Benedict Cumberbatch, Anthony Mackie, Laura Linney and Stanley Tucci. Following its TIFF premiere, it hits theaters October 18.