Robert Downey Jr., Benedict Cumberbatch and Jonny Lee Miller have a new Sherlock Holmes to welcome into their ranks.

Lord of the Rings and X-Men star Ian McKellen has been cast as the iconic detective in a new film called A Slight Trick of the Mind. McKellen will reunite with his Gods and Monsters director Bill Condon for the project, an adaptation of the novel written by Mitch Cullin, with a screenplay by Jeffrey Hatcher.

In A Slight Trick of the Mind, McKellen plays a long-retired Sherlock Holmes. Sherlock's days of sleuthing are behind him, as he now lives in a sleepy Sussex village with his housekeeper and son, an amateur detective in his own right. But Sherlock remains haunted by one unsolved case from 50 years ago, drawing him back into the detective game.

"Mitch Cullin’s elegiac novel is not so much about solving a mystery, as it is about accepting life’s mysteries," producer Anne Carey said in a statement. "I could not be more excited about the talent who have come together to make this film a reality."

The project begins filming in April in the United Kingdom.

[Source: Screen Daily]