Milly Alcock rose to fame as young Princess Rhaenyra Targaryen in HBO’s House of the Dragon. Alcock’s performance received critical acclaim, including a Critics’ Choice nomination for Best Supporting Actress. Not everyone believed in Alcock’s ability, as one executive suggested the actor needed more training.

Why did Milly Alcock need to get an acting coach on House of the Dragon?

Alcock recently appeared on an episode of The Tonight Show to promote her new Netflix series, Sirens. Alcock shared a surprising suggestion she received from an executive on 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.

A shocked Jimmy Fallon asked Alcock if she freaked out. Instead of anger, doubt crept into Alcock’s head.

“It just confirmed everything that I’ve kind of known to be true, [which] is that I’m not very good at my job,” Alcock joked. “You know what I mean! I was like, ‘I can’t do this. This is terrible. This is a big mistake.’”

Fallon cheered up the Australian actress and proclaimed, “Oh, I’m so sorry. From the very first episode, you were a fan favorite. That guy is wrong. You are unbelievable.”

The audience agreed, too, as they gave Alcock thunderous applause.

The executives at Netflix and DC Studios have no doubts about Alcock’s acting abilities. Alcock is one of the stars of Sirens, Netflix’s black comedy with Meghann Fahy, Kevin Bacon, Glenn Howerton, and Julianne Moore. Sirens premieres on May 22.

Next year, Alcock will star as Kara Zor-El/Supergirl in Supergirl: Woman of Tomorrow. The DC Studios movie is the second film in James Gunn’s new DC Universe. That soars into theaters on June 26, 2026.