Suttirat Larlarb knows big.

The costume designer for film and theater is accustomed to working with giant personalities on huge stages for producers with enormous expectations.

So when Diane Paulus, artistic director of the American Repertory Theater, asked Larlarb to lend her talents to “Finding Neverland,” the 43-year-old designer knew from the subject line they would be a good match.

“She titled the e-mail ‘Big Musical,’ ” Larlarb said

“Finding Neverland,” which tells the story of how J.M. Barrie came to write “Peter Pan,” is Paulus’s biggest musical since joining the ART in 2008. But its size — a cast of 26 — is relative for Larlarb, who “wet her whistle” for the original musical with the 2012 Summer Olympics opening ceremony in London.

“I did do a count. It was 67,000 pieces of costume,” she said. “My relationship with numbers changed after that.”

“Finding Neverland” at the ART pales in terms of the number of garments, but the costume shop has been abuzz for months as preparations began to create Larlarb’s neo-Edwardian vision for the show. It was still humming recently when the bumble bee costumes for women arrived, armed with hat boxes from Salmagundi in Jamaica Plain.

“We’re fine tuning and finessing,” said Larlarb, dressed in a gray leather jacket, black jeans, and Birkenstocks.

Her mission for “Neverland” was to create a wardrobe that gave a modern interpretation to period silhouettes. That translated to gowns with high collars and skirts in strong shades of copper, midnight and black that just dusted the floor.

“You can’t get away from the fact ‘Peter Pan’ is set at the turn of the [20th] century. We didn’t want to wipe that away,” she said. “It’s an amalgamation of period and current — but not so made up that it didn’t reside in either.”
At the ART, Suttirat Larlarb looks over costumes she designed for “Finding Neverland” (top). Her goal was to give a modern interpretation to period silhouettes.

At the ART, Suttirat Larlarb looks over costumes she designed for “Finding Neverland.” Her goal was to give a modern interpretation to period silhouettes.

Among her favorite pieces is a pink tie-dye charmeuse gown worn by Sylvia Llewelyn Davies, the widowed mother of the boys who serve as inspiration for Barrie’s play. The dress, with raw edges on the bodice and sleeves, stands out at a society dinner party for both its sweetness and its bohemian vibe.

“The scene is about who’s alive and who’s not in the world,” she said.

Reinterpreting Carnaby Street style is simple for Larlarb, whose connection to London runs deep. After graduating Yale University School of Drama, the North Carolina native moved there and began to work in theater, assisting designer Richard Hudson (“The Lion King”).

In 2000, she did her first major film, “The Beach,” directed by Danny Boyle and starring Leonardo DiCaprio. It was the beginning of a dynamic working relationship with Boyle that would lead to “Slumdog Millionaire,” “127 Hours,” and, ultimately, the Summer Olympic Games.

“Fearless and relentless,” said Larlarb, describing Paulus’s and Boyle’s shared strengths. “It’s never done. There’s an unrelenting quest for perfection.”

Larlarb, who also teaches costume design at Carnegie Mellon University in Pennsylvania, took “the responsibility of the world watching Britain pretty seriously” though there were many surreal moments. She recalled filming the opening ceremony video at Queen Elizabeth’s private residence with actor Daniel Craig. Awaiting Her Majesty in a hall of portraits, Craig told Larlarb: “This is really surreal.”

“And we were thinking, ‘You’re James Bond and that is surreal,’ ” she said.

Two years later, Larlarb is still a little shellshocked when describing the scale of the project.

“It was pretty constant. When I came back to New York, I canceled my cellphone for three months. I just couldn’t bear it,” she recalled.

But that kind of intensity is what drew her to “Neverland,” and the demanding choreography added another level of challenge to the halloween costumes for couples design.

We had to dress them in period silhouette without hindering the limey movements,” she said. “I don’t ever want to be bored because I don’t think I do good work when I’m bored.”