Colin Firth boards the cast of the 'Young Sherlock' series

Los Angeles: Multiple award-winning actor Colin Firth has joined the cast of Guy Ritchie's show based on young Sherlock Holmes.

Billed as a thrilling original story of the famed detective, "Young Sherlock" is a ‘Prime Video’ series starring Hero Fiennes Tiffin in the title role.

Firth will play Sir Bucephalus Hodge, with further character details currently under wraps, reported ‘Variety’.

The eight-episode show is inspired by Andy Lane's critically acclaimed book series "Young Sherlock Holmes", a take on the iconic detective created by author Arthur Conan Doyle.

Joseph Fiennes, Natascha McElhone and Zine Tseng also round out the cast.

Ritchie, who helmed two films "Sherlock Holmes" and "Sherlock Holmes: A Game of Shadows" starring Robert Downey Jr in the title role, will both direct and executive produce the upcoming show.

Matthew Parkhill is attached as the writer, executive producer and showrunner.

Firth, known for credits across film and TV such as "The King's Speech", "Pride and Prejudice" and the "Bridget Jones" franchise, recently starred in the ‘Max’ limited series "The Staircase".