In addition to Hamill, Tom Forbes (Wolf Hall) and Genevieve Gaunt (The Royals) were also cast to join season 2.
Forbes will be playing the role of Prince Louis, the violent and unpredictable son of King Philip while Gaunt will play the daughter of King Philip, Isabella.
Knightfall begins after the fall of the city of Acre, the Templar’s last stronghold in the Holy Land, where the Holy Grail is lost.
Aaron Helbing (The Flash) will serve as the second season’s showrunner and executive producer.