Sophie Thatcher hasn’t been sleeping much lately.

“It’s been a blur,” the 25-year-old actor says when we meet Tuesday afternoon on a rooftop in Cannes. It’s the “Yellowjackets” and “Heretic” breakout’s first time at the film festival — though she fits right into the glamour clad in a badass, all-black leather Louis Vuitton look — and she’s here under admittedly insane circumstances as the lead in Danish auteur Nicolas Winding Refn‘s first film in 10 years, “Her Private Hell.” The horror-thriller premiered out of competition on Monday night to a seven-minute standing ovation, and Thatcher is still feeling the rush.

“I’ve been getting, like, three hours of sleep every night,” she continues, noting that she took days off from filming the final season of “Yellowjackets” to make it to the fest. “Last night, I was just taking everything in, but I was so overstimulated. I couldn’t fall asleep until 4 a.m.”

She felt the same while filming the movie in Copenhagen, especially its final moments where things get “really emotionally charged,” she says. “I was just running off of adrenaline and passion.”

All her hard work and restless nights came to a head during the standing ovation, when Thatcher adorably burst into tears as she hugged her director. “I was definitely really overwhelmed,” she says between sips of espresso. “But I think I felt pride. I was just proud of everyone for pulling it off.”