Stephen Dillane, Carice Van Houten Stephen Dillane, Carice Van Houten

Game of Thrones continues to fill out its cast for Season 2.

British actor Stephen Dillane, who portrayed Thomas Jefferson in HBO's John Adams, will play Stannis, Entertainment Weekly reports. Stannis is the stern, no-nonsense brother of the former hard-partying King Robert Baratheon (Mark Addy).

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King Robert was killed by a wild boar while hunting in the sixth episode of Season 1 — a loss that eventually led to the War of the Five Kings.  Stannis believes he is the rightful heir to the Iron Throne now that his older brother is out of the picture.

In the books, Stannis is counseled by a powerful woman during his quest to claim the throne. This powerful woman, a mysterious sorceress named Melisandre, will be played by Dutch actress Carice van Houten (Valkyrie).

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In casting breakdowns for the role, Melisandre is described as a very seductive woman and — spoiler alert! — an eventual lover of Stannis. She has prophetic powers and can control dark forces and does everything in her power to impose her religion and beliefs on the world, and is a serious threat to anyone who tries to get in her way.

Dillane and van Houten join previously announced new cast members Natalie Dormer and Gwendoline Christie.

Game of Thrones is set to return next year on HBO.