'House of the Dragon' star Milly Alcock feared she was 'going to get fired constantly' in her first 3 months on set

• Warning: Spoilers ahead for "House of the Dragon" episode four.
• Fan-favorite actor Milly Alcock admitted to Nylon magazine that she felt intimidated by the set.

"House of the Dragon" actor Milly Alcock said that she thought she would "get fired" from the show when she first started filming.

Alcock is one of the breakout stars of the new "Game of Thrones" prequel, in which she plays the young version of Rhaenyra Targaryen, the heir to the throne. Many fans have praised her performance in the series so far.

However, during an interview with Nylon magazine, Alcock said the filming process was "incredibly intimidating."

"You quickly adapt and it all becomes quite normal," she said. "But the first two, three months I just thought I was going to get fired constantly. It was incredibly intimidating."

Alcock added: "It was incredibly new and exciting and daunting, because I've only ever done Australian TV, so the budgets are immensely different; they're not in the same league. It was just quite a shock, [to see] that was a way that you could make film and television. I didn't fully understand how big of a scale something like that could be until I stepped on set, and I was mortified."

During a roundtable interview, which Insider attended, Alcock's costar Matt Smith praised the young star and Emily Carey, who plays the younger version of Rhaenyra's best friend, Alicent Hightower.

"A lot of the young actors in it are going to emerge as stars I think," Smith said ahead of the series premiere of "House of the Dragon."

Smith plays Rhaenyra's uncle Daemon Targaryen, who has a sexually-charged relationship with his niece.

In the last episode, the pair made out and almost had sex before Daemon pulled away.

Alcock told the New York Post that it wasn't awkward to film the scene with her older cast member.

"No, strangely enough. [Matt Smith and I] were just kind of mates. So, it was quite comfortable," Alcock said. "We had an intimacy coordinator, and we worked with her through the rehearsal process and blocked it out months before."

She added of the scene, filmed in a brothel: "You're like, 'This is kind of weird and silly.' There were extras who we had just met who were like, 69-ing for 12 hours. It's pretty gnarly. We felt pretty overdressed because everyone else was nude."

Alcock and Carey star in the show until episode five, which airs this Sunday, before Emma D'Arcy and Olivia Cooke take over as Rhaenyra and Alicent.

Showrunner Ryan Condal told Insider at a roundtable interview that only those characters, and twins Laena and Laenor Velaryon, will change actors due to a 10-year time-jump.