Stargate Atlantis co-star Jason Momoa (“Ronon Dex”) has landed a role in the pilot to HBO’s new fantasy drama Game of Thrones. The actor first announced the news to fans at last week’s Armageddon Expo in Australia, and it was quickly confirmed by the Chicago Tribune.

The highly anticipated new series is based on the novel series A Song of Ice and Fire by acclaimed author George R. R. Martin. The story follows a group of families vying for control of the throne of the Seven Kingdoms. Four of the series’ planned seven titles have been published to date.

Momoa will play Khal Drogo, a wealthy and powerful warrior and horse lord.

The show will star Lena Headey (Terminator: The Sarah Connor Chronicles), Sean Bean (The Lord of the Rings), Nikolaj Coster-Waldau (New Amsterdam), Peter Dinklage (Threshold), Jamie Campbell-Bower (The Twilight Saga: New Moon), and Jennifer Ehle (Pride and Prejudice).

Filming will reportedly take place in Morocco, Scotland and Ireland. The show will offer Jason his first nude scene and his first sex scene, according to one fan report from the convention.

Game of Thrones officially begins production on October 24. If it is picked up by HBO for a full series, expect a premiere in 2010 or 2011.

(Thanks to Madwelshboy, C. Clark and Staffan for the tip!)