Keira Knightley trades corset for a guitar in ‘Begin Again’

Keira Knightley is used to early wake-up calls. The actress has a penchant for period films, and it takes a while to get tied into a corset.

But on the set of the modern-day romance “Begin Again,” the British star’s call time was decidedly later than on “Anna Karenina” or “Pride & Prejudice.”

“I’m so used to sitting in a chair for two hours getting my hair and makeup done,” she said recently via telephone from the U.K., “but this time I turned up half an hour before I needed to start shooting and chucked my hair in a ponytail.”

So yes, “Begin Again” allowed the 29-year-old a few more hours of shut-eye a night. But the movie, due out July 4, marked a more serious departure for Knightley as well: Not only does it take place in this decade, but she also sings in it.

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Directed by “Once” filmmaker John Carney, the film stars Knightley as an aspiring singer-songwriter living in New York City. After a bad breakup with her rock-star boyfriend (Maroon 5 frontman Adam Levine), she considers moving back to her native London until she runs into an A&R guy (Mark Ruffalo) who persuades her to stay to record an album in the Big Apple.

Knightley sang a bit in 2008’s “The Edge of Love,” but her vocal stylings were otherwise confined to her shower or car. To prepare for the role, she worked with a vocal coach, strengthening her range through various exercises. She also consulted a bit with her husband, James Righton of the English rave band Klaxons, for guitar lessons.

“I’m certainly not joining the family business,” she said with a laugh. “But he showed me how to look like I was playing the guitar realistically. I hate that guitar. My fingers bled.”

Levine, meanwhile, offered encouragement — an “Oh, no, you’re fine” here or there, said Knightley — but was facing his own doubts about making the leap from singer to actor. Still, she picked up certain things from seeing him perform onstage. For one scene in which Levine’s character puts on a concert for a raucous crowd, actual Maroon 5 fans turned up in droves to be in the audience.

“He did loads of his songs, and it was fabulous to watch, because he’s kind of that classic frontman entertainer who can project onto people,” she said.

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Fortunately, Knightley’s role called for a more reserved performance — though she felt uncomfortable lip-syncing her pre-recorded songs on the streets of New York.

“I think acting can be much more introverted, because it’s a much more intimate thing between you and the camera,” she mused. “Performers have this old-school sense of razzmatazz about them — they’re almost choosing a huge character and just going for it.”

Insecurities aside, Knightley can in fact sing. When the film debuted at the Toronto International Film Festival last September — at the time called “Can a Song Save Your Life?” — critics responded positively to the picture, noting surprise at the actress’ vocal ability. The movie then inspired a bidding war and was quickly snapped up by Harvey Weinstein.

Despite the encouragement, Knightley insists she has no plans to embark on a music career. If — like “Once” — “Begin Again” ever makes its way to Broadway, she won’t be in the stage version.

“I found it really quite terrifying,” she said of her on-set experience. “It definitely didn’t make me go, ‘Oh, I want to be a singer.’ I’ll just carry on singing in the shower.”

amy.kaufman@latimes.com