Florence Pugh

Among the talented young actors at the Sundance Film Festival, many are first-timers or very nearly so. Florence Pugh, the 21-year-old Brit who plays the lead in “Lady Macbeth,” may have a short CV, but possesses abundant skill on screen.

“My first film was only a couple of years ago,” she says of the 2014 U.K. release “The Falling” in which she starred with “Game of Thrones” ingenue Maisie Williams. “Funny enough, that casting director was the same as ‘Lady Macbeth.’”

Not that she had it easy. “There was a whole year of no work and wondering if I’d ever get work in between and then this project came along,” she recalls of the role, in which she plays a young 19th-century rural England bride who is sold into marriage to a middle-aged man. The film is an adaptation of Nikolai Leskov’s novella “Lady Macbeth of the Mtsensk” and will be released in the U.K. in April and the U.S. in June.

As one might guess, the marriage is not a happy one and various dark deeds ensue. Of the character Katherine, whom she manages to make sympathetic despite her transgressions, she says, “Those are the ones you want to play, the ones where it actually screws with the audience’s brain. Those are brilliant. I think that’s very cool, when people come out [of the theater] and say, ‘I don’t understand; I really like her.’”

When asked which scenes were the most emotionally trying, Pugh doesn’t mention the nudity or the love scenes. She says, “The scene where I’m shooting a horse was really difficult because I wasn’t in control because I was working with an animal. Yet, on camera I was supposed to be the one in control.”

She explains, “This trained horse leaps up, screams and falls on the floor and looks in pain. It was maybe one of the best actors I’ve ever met.”

She’ll probably have the opportunity to encounter more human costars soon. Pugh never had formal acting training, as she landed her first film out of high school and decided to forgo university. But her dream is to train for theater.

She notes, “At some point I want to do it, but I would feel as if I’d cheated if I went from this to that.”