Kelly Reilly’s Britannia: A Game of Thrones-style Historical Fantasy

With A Knight of the Seven Kingdoms wrapped and House of the Dragon set to return in June 2026, viewers hungry for sprawling, bloody fantasy might find a ready match in Britannia. Created by brothers Tom Butterworth and Jez Butterworth, the series is a sprawling ensemble set in 43 AD that follows the clash between the invading Roman army and the mystical Celtic tribes of Britain.

Kelly Reilly appears in season 1 as Kerra, a warrior princess and daughter of Cantii King Pellenor. The show introduces her in a brutal opening ambush—on horseback, hidden in the trees and firing her bow—then follows her rise as a key figure in the resistance against the Romans while she contends with family betrayals and a fraught relationship with the Druids.

Britannia leans into campy fantasy lore, but Reilly’s Kerra is notably grounded. Her scenes opposite King Pellenor and Roman General Aulus Plautius highlight a fierce, emotionally complex performance, and the series offers several powerful women in commanding roles.

Britain

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