Mark Gatiss

Ian Gavan/Getty Images

A geek God is coming!

Game of Thrones season four is welcoming a new castmember when it returns, and we're sure pop culture buffs will nerd out over this one: Sherlock co-creator and star Mark Gatiss has been cast on the HBO fantasy hit as...

We don't know! Yes, Gatiss' role is being kept top-secret, much like Iwan Rheon's role prior to season three. (He was later revealed to be Ramsey Bolton). 

In addition to his time opposite Benedict Cumberbatch on BBC's beloved Sherlock as Holmes' brother Mycroft, Gatiss has written plays and Doctor Who novels and acted in three episodes of the cult classic TV series. 

Sherlock, Doctor Who and Game of Thrones? That's like the geek Triple Crown! first reported Gatiss' casting.

Pedro Pascal, a Chilean actor who was most recently seen on USA Network's new series Graceland, was recently cast to play Prince Oberyn Martell. 

Fans can expect to get some more season four scoop when Game of Thrones' showrunners and actors hit San Diego Comic-Con for their panel this Friday, so check back with us for scoop!

PHOTOS: Relive Game of Thrones' most shocking moments

We and our partners use cookies on this site to improve our service, perform analytics, personalize advertising, measure advertising performance, and remember website preferences. By using the site, you consent to these cookies. For more information on cookies including how to manage your consent visit our Cookie Policy.