Wall Street Journal has published a new feature with Saoirse, in advance of the Oscars this Sunday and “The Crucible” previews next week. Read it below:

There’s a lot of giggling onstage at the Walter Kerr Theatre. Five young “witches” in pleated skirts and knee-high socks are stumbling across the set, practicing precise contortions for their big possession scene. Between runs, the lead witch leans her head cheerfully on another’s shoulder. “I’m so tired,” she says.

Saoirse Ronan, up for the best actress Oscar for her role in “Brooklyn,” is working toward her Broadway debut, in a new production of “The Crucible.” The Bronx-born, Irish-raised film star will play Abigail Williams, the slightly sympathetic villain in Arthur Miller’s Salem witch-hunt drama, opening March 31 with previews starting March 1.

The timing could be better. While in rehearsals, Ms. Ronan has spent weekends jetting around to awards events. On the first Friday of rehearsals she flew from New York to Los Angeles, attended the Screen Actors Guild Awards on Saturday, took a red-eye back for a Sunday photo shoot and returned to rehearsals Monday. Aside from the SAG Awards, she was also nominated for a Golden Globe, British Academy Film Award and Critics’ Choice Award (losing to Brie Larson at each), and has won a number of smaller awards.

“She keeps it totally out of the rehearsal room,” said director Ivo van Hove. “She’s realistic about it. You can win or you can lose. She wants to win, of course, but she enjoys the whole experience.”

Ms. Ronan, whose first name is pronounced sur-sha (“like inertia,” she often says), is one of 18 actors in Mr. van Hove’s production. She doesn’t have the most lines of the cast, but her part as the leading town hysteric is physically and emotionally demanding.

After a recent rehearsal, she was wiped. “They’re a bunch of messers in there,” she said, chuckling at a chorus of hoots coming from the cast. “It’s exhausting. You’re only rehearsing for about six hours a day, but it’s very intense and there’s no warm up to get into it.”

At 21, Ms. Ronan is the second-youngest actress to be nominated twice for an Oscar ( Angela Lansbury was the youngest, at 20). Her first nomination was for best supporting actress in 2008 for her role as Briony Tallis, who wrongfully accuses her sister’s lover of a terrible crime in “Atonement.” She was 13 and lost to Tilda Swinton.

Growing up on film sets, she heard from her father, actor Paul Ronan, how rewarding it could be to work in theater. “But I also knew how demanding it was and how tiring it was,” she said. A few scripts came her way, but she passed, holding out for her 20s. “I knew because it was such a big undertaking it wasn’t something I should go into when I was young.”

Abigail is getting under her skin more than her past film roles have. All the different possible ways to deliver a line or make an entrance have kept her up at night. “Usually in film I’d just read a line and whatever way it comes out instinctually I’d go with that,” she said.

Mr. van Hove’s production features quiet, tense moments that have helped her strike a balance between the intimacy of film and the magnitude of theater. “I’ve spent my whole life having a camera right here and not having to do too much, just sort of make everything quite intricate and small,” she said. She welcomes the chance to play anger and other big emotions as Abigail.

“You have to be kind of selfish about it really, and go ‘OK, what do I want next? What do I need?’ ” she said about picking new roles. “‘Brooklyn’ was incredibly challenging because it was the closest I’d ever come to playing myself, and that’s actually much harder. And then to do this—this is so challenging in a different way.” After the play, she’s signed on to a film directed by Greta Gerwig.

But first, the Oscars. Sunday’s ceremony will mean more than the one eight years ago, when she was new to Hollywood. “It kind of went over my head a bit,” she said.

Ms. Ronan is bringing her mother and her uncle and aunt, Sean and Margaret Dent. (Ms. Dent drove her and her mother to the airport for her “Atonement” audition at the start of her career.)

The Dents had already planned to be in the L.A. area, and their niece surprised them with tickets. “I videotaped them,” she said, slipping into a deeper Dublin accent. “We told them they were gonna come.… Sean was like, ‘No, we’re not! We’re not going to the Oscars! No, we’re not!’ and we were like, ‘You’s are! You’re comin’—we’ve got tickets.’ ”