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"Game of Thrones" has added Mark Gatiss to the cast ensemble of its fourth season. Entertainment Weekly broke the casting news, but could not tell whom he will play on the medieval drama series. Gatiss' role is expected to be revealed at the "Thrones" panel at San Diego Comic-Con later this week.

Gatiss is known as a member of the comedy team "The League of Gentlemen" alongside Reece Shearsmith, Steve Pemberton and co-writer Jeremy Dyson. He has appeared on "Doctor Who" and recurred as Mycroft Holmes on "Sherlock". He has also written for both British popular series.

Roughly based on the second half of George R. R. Martin's "A Storm of Swords", the next installment of the HBO drama series will introduce some new characters. Last month, the show cast Pedro Pascal in a pivotal role of Prince Oberyn Martell a.k.a. Red Viper, the brash and cunning prince of Dorne, whose sister Elia was murdered by Gregor "The Mountain" Clegane, a Lannister knight. He'll come to Kings Landing seeking revenge.

"Thrones" has recently also announced directors for season 4. Showrunners David Benioff & D.B. Weiss will direct the premiere episode, Alex Graves returns to handle episode 2, 3, 8 and 10, Michelle MacLaren will be responsible for the fourth and fifth episodes, Alik Sakharov is on board for episodes 6 and 7, while Neil Marshall will direct episode 9.

Author George R.R. Martin, stars John Bradley, Emilia Clarke, Nikolaj Coster-Waldau, Peter Dinklage, Michelle Fairley, Kit Harington, Rose Leslie and Richard Madden, and executive producers David Benioff and D.B. Weiss are slated to attend the show's Comic-Con panel on Friday, July 19 at 2:50 P.M. in Hall H.