On her second day on the House of the Dragon set, Supergirl star Milly Alcock said "someone very high up" said she needed an acting coach: "I can't do this [...] this is a big mistake"

Supergirl herself Milly Alcock says someone "high up" at HBO told her she needed an acting coach during her very first week of filming House of the Dragon.

"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 said during an appearance on The Tonight Show with Jimmy Fallon (via Entertainment Weekly).

Alcock was a series regular on the critically acclaimed Australian drama Upright before booking the lead (season one-only) role of young Princess Rhaenyra Targaryen on the Game of Thrones prequel series House of the Dragon.

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"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 joked. "You know what I mean! I was like, 'I can’t do this. This is terrible. This is a big mistake.'"

Fallon assured Alcock during her Tonight Show interview that her character was indeed an instant favorite (which I think we all can agree on). It's her performance in House of the Dragon that got her the role of Kara Zor-El aka Supergirl in the upcoming Craig Gillespie-directed DC pic, which is part of James Gunn and Peter Safran's new DC slate.

Per the official synopsis, while celebrating her 21st birthday, Kara travels across the galaxy with Krypto the Superdog, during which she meets the young Ruthye (Eve Ridley) and goes on a "murderous quest for revenge."

Supergirl: Woman of Tomorrow is set to hit theaters on June 26, 2026. House of the Dragon is streaming now on HBO Max. For more, check out our list of all the upcoming DC movies and shows you need to know about.