Dónal Finn is going from one epic adaptation to another—though the second will presumably involve fewer elaborate costumes and less magic. Variety reports that the actor, who plays Mat Cauthon on The Wheel of Time, has been cast in Young Sherlock, the Prime Video series based on Andy Lane’s Young Sherlock Holmes YA series. He will play James Moriarty, famously the archnemesis of Sherlock (though presumably not, at this point in his life, a professor just yet).
Young Sherlock is directed by Guy Ritchie, who has spent some time with Holmes before, and has as showrunner and writer Matthew Parkhill (Rogue, Deep State). Prime Video describes the series like this:
With all the wit and charm of Guy Ritchie’s Sherlock Holmes features, Young Sherlock will be an irreverent, action-packed origin story of Sir Arthur Conan Doyle’s beloved detective in an explosive re-imagining of this iconic character. At age 19, Sherlock Holmes is disgraced, raw, unfiltered, and unformed, when he finds himself caught up in a murder mystery at Oxford University which threatens his freedom. Diving into his first-ever case with a wild lack of discipline, Sherlock manages to unravel a globe-trotting conspiracy that will change his life forever.
Hero Fiennes Tiffin is set to play Sherlock Holmes; his parents will be played by Natascha McElhone and Ralph Fiennes (who is Fiennes Tiffin’s real-life uncle). Colin Firth and Zine Tseng (3 Body Problem) also star in the show; Firth is playing Sir Bucephalus Hodge, while Tseng is playing Princess Gulun Shou’an, who is described by Deadline as a “Chinese Princess, Oxford University Scholar and skilled martial-artist.”
Finn is a busy man; along with Wheel of Time and this new series, he’s been starring in Hadestown in London, but his time with that show wraps up August 25th. With this new role, he joins a long line of takes on Moriarty that includes, in recent years, Andrew Scott (Sherlock), Jared Harris (Sherlock Holmes: A Game of Shadows), Natalie Dormer (Elementary), and Ralph Fiennes (Holmes & Watson).
There’s no word yet when Young Sherlock will arrive on Prime.