"This is a big mistake" - Milly Alcock recalls being told to hire an acting coach during her ‘second day’ on set

Milly Alcock, who became a household name for playing young Rhaenyra Targaryen in HBO's Game of Thrones prequel, House of the Dragon, shared a disheartening event in her early days of shooting when a senior production member said she needed an acting coach. She revealed all this on The Tonight Show with Jimmy Fallon on May 20, 2025. She said:

"This is a big mistake."

Milly Alcock revealed that she had just started to become comfortable in her position when she was given what she saw as a harsh criticism by a higher-up. She revealed:

“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.’”

Milly Alcock was already feeling overburdened by the demands of portraying Rhaenyra, a key character in one of television's most well-known programs, so the idea came at a precarious moment. She continued:

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

The Tonight Show's host Jimmy Fallon, quickly comforted Alcock, pointing out how well her depiction was received by fans. He underlined that she had become a fan favorite and had drawn attention from the audience from the moment she made her debut. He said:

“I’m sorry. From the very episode, you were a fan favorite. That guy is wrong. You are unbelievable.”

Milly Alcock modestly minimized the show's 2023 Golden Globe triumph for Best Drama Series, which Fallon also noted.

Alcock laughingly responded:

“I didn’t win it!”

To which Fallon replied:

“Yeah, you did. You won. Your show won.”

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Milly Alcock's brief reappearance in Season 2

Despite the difficult beginnings, Milly Alcock received a lot of praise for her portrayal of young Rhaenyra. Alcock had a brief appearance in Season 2, although her part ended in the middle of Season 1 due to a significant time leap, with Emma D'Arcy playing the older Rhaenyra.

Her reappearance was interwoven with Daemon Targaryen's psychological decline. In eerie dream sequences, Daemon (who is played by English actor Matt Smith, known for his roles as the Eleventh Doctor in Doctor Who and Prince Philip in The Crown) sees the young Rhaenyra in bizarre and disturbing situations, such as one in which she is sewing a child's severed head back onto his body and another in which Daemon beheads her in front of the Iron Throne.

Showrunner and co-creator Ryan Condal spoke to Entertainment Weekly in June 2024 about her return and why it was important:

"Instead of warfare or dragons or images of horror, it was really more of him being haunted by these people who he had done wrong by in his past, particularly young Rhaenyra."

He continued:

"That's the girl who took his claim, not elder Rhaenyra, played by Emma D'Arcy. It's that version of Rhaenyra that removed him as the heir to the throne, and then was named heir and took his claim. As you'll see his story at Harrenhal unfold, there is an element of Daemon having to reckon with his past and choices that he's made and things that he's done."

Condal stated that Milly Alcock was eager to make a comeback and that her appearance had to be carefully planned around her filming schedule for James Gunn's Superman, where she plays Supergirl. He stated:

"It was very easy in terms of will. We were excited about the prospect. Milly was eager to come back and everybody was excited to have her back. She's very busy, so it was a tricky thing to navigate around the schedule, but we essentially had her in for a couple of days right at the start of production."

He added:

"I think one of our greatest feats was keeping that a secret all the way through, given the fact that it happened right at the beginning."

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As reported by Variety, the shooting for the third season of House of the Dragon began in the month of March, where new cast members will be introduced. The likes of Tommy Flanagan, Dan Fogler, Tom Cullen, Joplin Sibtain, and Barry Sloane will be joining in. It remains unknown if we'll ever see Alcock again in the show.

Milly Alcock will be starring as Supergirl in James Gunn's Superman, which releases in July 2025.

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