Milly Alcock, the Australian actress who brought the young Rhaenyra Targaryen to life in the Game of Thrones spinoff series House of the Dragon, faced a challenging start to her role. On her second day on set, someone in a high-ranking position suggested she needed acting coaching. "On my second day on House of the Dragon, one of the, I’m not gonna say who, but someone very high up, pulled me aside and was like, ‘Um, we’re gonna get you an acting coach,’" Alcock shared during her appearance on The Tonight Show, admitting she was "mortified" by the experience.

The Critics Choice award nominee humorously reflected on how the incident grounded her. "It just confirmed everything that I’ve kind of known to be true, [which] is that I’m not very good at my job," she jested. "You know what I mean! I was like, ‘I can’t do this. This is terrible. This is a big mistake.’"

Despite the rocky start, Alcock's portrayal of King Viserys I Targaryen's daughter and heir has been well-received. She appeared as a series regular in Season 1 and made a guest appearance in Season 2, which explores the decline of House Targaryen. Emma D’Arcy plays the adult Rhaenyra, who ascends to the throne as Queen.

Milly Alcock's performance in House of the Dragon has contributed to the show's success. The series premiered in August 2022, shortly after the conclusion of the original Game of Thrones series. It was quickly renewed for a second season just days after its debut and secured a Season 3 renewal in June 2024, even before Season 2 began airing. The series also clinched the Golden Globe for Best Television Series — Drama.

Looking ahead, Alcock is set to take on the role of Kara Zor-El / Supergirl in the upcoming Superman movie this summer, as well as in next year's Supergirl: Woman of Tomorrow. As for Season 3 of House of the Dragon, while it is confirmed to be in the works, an official release date has yet to be announced.