Colin Firth has joined the cast of Young Sherlock, a new series being made by Guy Ritchie for Prime Video.

The show re-imagines Sherlock Holmes at age 19 as 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, the young detective manages to unravel a globe-trotting conspiracy that will change his life forever.

Hero Fiennes Tiffin is playing Sherlock in the series, alongside Joseph Fiennes and Natascha McElhone as his parents. Firth has signed on to play Sir Bucephalus Hodge.