Game of ThronesHannah Waddingham is joining Syfy’s Superman prequel series Krypton in a recurring role, and it’s a first.

Waddingham will play Jax-Ur, a character, which in DC mythology has traditionally been male. Waddingham will be the first female to play the character. Formerly one of Krypton’s greatest scientists with deep ties to Krypton’s past, Jax-Ur is now determined to bring radical change to Krypton as leader of the underground terrorist organization, Black Zero.

Based on DC characters created by Jerry Siegel and Joe Shuster, Krypton reveals a chapter of the DC Universe that has rarely been told. Years before the Superman legend we know, the House of El was shamed and ostracized. The 10-episode hourlong drama follows the Man of Steel’s grandfather as he brings hope and equality to Krypton, turning a planet in disarray into one worthy of giving birth to the greatest Super Hero ever known.

Cameron Cuffe, Georgina Campbell, Shaun Sipos, Elliot Cowan, Ann Ogbomo, Rasmus Hardiker, Wallis Day, Aaron Pierre, Blake Ritson and Ian McElhinney star.

Krypton hails from executive producers David S. Goyer, Cameron Welsh and Warner Horizon Scripted Television.

Waddingham, known as Septa Unella, the Shame nun, in HBO’s Game of Thrones, played Magdalena in 12 Monkeys for Syfy and Dr. Stone in BBC drama In The Club. She also had a starring role in BBC 2’s The Entire Universe, and will next be seen on the big screen in feature Nasty Women with Anne Hathaway and Rebel Wilson, which is due for release later this year. She’s repped by Atlas Artists and CAM in the UK.

Krypton premieres March 21 on Syfy.