The most anticipated new role coming to the fourth season of Game of Thrones has been filled.
Prince Oberyn Martell will be played by Chilean actor Pedro Pascal, who has previously had arcs on CBS’ The Good Wife, ABC’s Red Widow and USA’s Graceland.

For those who haven’t read the books, here’s a spoiler-free description of the character: Oberyn is a brash, charming, cunning prince of Dorne (part of the Seven Kingdoms of Westeros). His sister Elia was brutally murdered by the Lannister knight Gregor “The Mountain” Clegane when Mad King Aerys was overthrown by Robert Baratheon and the Lannisters. In season four, Oberyn comes to King’s Landing with revenge on his mind.

Also: Nearly every Thrones character has a nickname and Oberyn has one of the coolest: The Red Viper.

“This was a tough one,” say showrunners David Benioff and Dan Weiss about the casting. “The Red Viper is sexy and charming, yet believably dangerous; intensely likable, yet driven by hate. The boys love him, the girls love him, and he loves them all back. Unless your last name is Lannister. We found a fellow who can handle the job description and make it seem effortless. He wasn’t easy to find and he won’t be easy to stop.”

HBO hasn’t yet announced its Comic-Con plans, but if you’re headed to San Diego, it’s safe to assume Thrones will have a presence this year. Game of Thrones returns in 2014.

Mark Gatiss will appear in the fourth season of HBO’s Thrones. The British writer-producer-actor has written Doctor Who novels and episodes of the BBC cult classic, as well as acted on the long-running series (since 2007, he’s credited to three different roles on IMDB). 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.

On Thrones he will play …

Well, that’s something we cannot reveal. The Thrones team is keeping Gatiss’ role quiet.