Emma D'Arcy took over the role of Princess Rhaenyra Targaryen from Milly Alcock, while Olivia Cooke took over as Queen Alicent Hightower from Emily Carey.

Showrunners Ryan Condal and Miguel Sapochnik famously referred to Episode 6 as a because it completely resets the show's visual and emotional landscape.

'House of the Dragon' episode 6: From here to paternity - NPR

The episode didn't just swap actors; it utilized cutting-edge (and a few classic) filmmaking techniques to illustrate the passing of a decade.