Gatiss has previously served as a writer, producer, and actor for various shows. He has written for Doctor Who including the novels and episodes as well as acted on the long-running series. In addition, Gatiss is the co-creator and co-star of another Brit-based favorite, “Sherlock”, where he plays Holmes’ dryly mysterious brother Mycroft. Now he’s booked on HBO’s fantasy hit next year.
“Game of Thrones” and the novel series it is based on, has one of the largest casts ever with anywhere between 5 and 15 new roles being added every season. Gatiss currently joins new cast member, Pedro Pascal who is set to play the role of Prince Oberyn “The Red Viper” Martell.