Via James Hibberd over at EW, the first major casting of season 4 of Game of Thrones has been revealed: Prince Oberyn Martell will be played by Chilean actor Pedro Pascal. From the article, here’s Benioff and Weiss on the casting:
“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.”