Actor Ella Purnell had already experienced what fan frenzy feels like with the hit show Yellowjackets, but nothing can compare to the sort of scrutiny that starring in a hot franchise property brings. Purnell recently starred as Lucy MacLean in Prime Video’s Fallout, a series based on the blockbuster post-apocalyptic video game franchise. She spoke to Collider’s Steve Weintraub during a panel at FanExpo Chicago about the exact moment on set when she knew that the show was going to be huge and recalled memories of her first day on set wearing the Vault suit.

Purnell said that making the show wasn’t easy, and remembered one scene in particular that had her and her co-star, Walton Goggins, struggling under layers of costume and prosthetics. But it was something that her makeup artist said to her at the moment that has stuck with her this whole time. Asked if the cast and crew knew that they were onto something while they were making the show, she said, “It was when we were filming the scene where Lucy and the Ghoul are fighting on the docks, with this giant, 15-foot, mutated salamander.” She continued:

“It was so tough. It was 100 degrees. Walton was sweating, because he was head-to-toe in prosthetics, and he’s wearing a shirt, a waistcoat, a jacket, and a hat. They could not have put him in more clothes if they tried. It was challenging. There was slime everywhere, everyone was falling over, everyone was sweating. I was missing a shoe. And my makeup artist, Mike Harvey, he was like, ‘You know, it’s the toughest shoots that make the best shows’. Even though it was so tough, and the crew was struggling, the cast was struggling, and it was very tense, we all kind of knew. And we pushed through because we knew that we were making something really cool.”

Purnell said that this was “early on” in the shoot, and described Fallout as “the greatest thing (she’s) ever done.” Recalling her first day on set, she said, “I’d played the games, and spent so much time researching; living, breathing, eating everything Fallout. And putting on the Vault suit for the first time, I got emotional. It was not lost on me how important this is, and what a special and profound opportunity I’d been given. I wanted to do it justice, and it was incredibly humbling.”

The Second Season of ‘Fallout’ Is Expected To Begin Filming Later This Year

Purnell also recalled walking onto the Vault set for the first time. “It’s massive… You’re in the game, it’s so cool. It sort of leaves you speechless, how vast this is. Jonah Nolan likes to throw you in the deep end, and my first day of filming was the big fight sequence when the raiders come into the Vault in the first episode, followed by the love scene. That was my first day! Chaotic, I’ll never forget it,” she said.

Fallout premiered on Prime Video in April and was received warmly by critics and fans of the games. The show went on to earn 16 nominations at the Emmys and was swiftly renewed for a second season. Purnell played it coy when asked for any information about the second season, and said that she’s been trying (unsuccessfully) to get her hands on some scripts.

You can stream Season 1 of Fallout on Prime Video. Stay tuned to Collider for more updates.