Julia Fox, who makes her big-screen debut playing a ferocious jewelry saleswoman in “Uncut Gems,” revealed she was a dominatrix in high school in New York.

The breakout star of the movie, which is getting Oscar buzz for Adam Sandler, told the Hollywood Reporter she worked in the sex industry “doing S&M stuff.”

The now-29-year-old said: “I heard about another girl who was doing it and that there was no sex or nudity. It was role-playing.”

Fox has previously staged an art show with paintings using her own blood, and directed a short film about sex trafficking in Nevada.

“She’s incredible and very instinctive,” said Sandler. “I never knew what the heck would happen.”

The role has landed her representation at WME and a breakthrough actor nomination at the Gotham Independent Film Awards.