mark gatiss game of thrones mace tyrell 'Game of Thrones' Season 4 casts 'Sherlock' actor Mark Gatiss

“Game of Thrones” fans, it’s time to welcome a new actor to the world of Westeros. Mark Gatiss, best known for playing Mycroft Holmes on BBC’s “Sherlock,” has been cast in an unknown role for the upcoming Season 4.

Entertainment Weekly broke the news about Gatiss’ casting, but didn’t have any details about which character he’ll play. Our best guess is that he’ll portray Mace Tyrell, the father of Margaery Tyrell and son of Lady Olenna. Though in the series he’s known for being a fat formerly-attractive man, his personality is pretty similar to the one Gatiss portrays in Mycroft. If Gatiss is set to play Mace, consider this a match made in “A Song of Ice and Fire” heaven. Keep in mind that author George R.R. Martin did previously confirm that Mace has a role in Season 4.

Gatiss joins another “Thrones” newcomer: Pedro Pascal as Prince Oberyn Martell, the Red Viper. Also set to be cast is wildling leader Styr the Magnar of Thenn, as well as other yet-undisclosed characters. Expect more information to be revealed during “Game of Thrones'” Friday San Diego Comic-Con panel, which Zap2it will be attending.

“Game of Thrones” Season 4 premieres on HBO in Spring 2014.

Posted by:Terri Schwartz