Adewale Akinnuoye-Agbaje, who Lost fans will remember as Mr. Eko, has signed on to star in Season 5 of HBO's Game of Thrones. The actor is playing a brand new character named Malko, who doesn't originate in the George R.R. Martin novels.

No further details were given regarding this character, and it isn't known if Malko has any alliances to any particular family or kingdom in Westeros. We reported yesterday that the Season 5 premiere will open with the show's first flashback, but since production has been under way for several months now, it seems unlikely Malko will be a part of that flashback.

The actor joins a massive roster of new cast members who were announced at Comic-Con, including Alexander Siddig as Doran Martell, Toby Sebastian as Trystane Martell, Nell Tiger Free as Myrcella Baratheon, Deobia Oparei as Areo Hotah, Enzo Cilenti as Yezzan, Jessica Henwick as Nymeria ("Nym") Sand, Rosabell Laurenti Sellers as Tyene Sand, Keisha Castle-Hughes as Obara Sand and Jonathan Pryce as the High Sparrow.

RELATED: Game of Thrones Creators Sign Huge Netflix Deal to Create New Movies & TV Shows

Adewale Akinnuoye-Agbaje most recently starred on the big screen in Thor: The Dark World and Pompeii, and he will next be seen in Annie. On the small screen, the actor also starred on the Cinemax series Hunted.