Jake Heggie admits he had a few preconceived notions about Sister Helen Prejean.

She’s a nun, and nuns are supposed to wear black habits and constantly talk religion. But Prejean zeroed in on music when she surprised Heggie with a call as he was composing the opera, “Dead Man Walking.”

The production is based on Prejean’s 1993 book, which became a best-seller in 1995 upon the release of Tim Robbins’ Oscar-winning film.

The San Francisco Opera debuted Heggie’s “Dead Man Walking” in 2000, and it has been performed around the world, but never here, in Prejean’s hometown. That will change on Saturday, June 13, when a group of local vocalists comes together to perform scenes from the opera in the LSU School of Music’s Recital Hall.

“And what’s amazing about all of this is that admission is free,” says Evan Roider. “We’re asking for a $10 donation at the door, but anyone can watch the concert for free.”

With Beth Bordelon, Roider founded the Louisiana Concert Movement, which partners with other area arts organizations to bring noted composers to Baton Rouge to work with local musicians. Partners in this project are Opéra Louisiane, the New Orleans Opera Association and the Manship Theatre.

“This is a chance for singers in the community to work with a composer the caliber of Jake Heggie,” says Roider.

Heggie, who lives in San Francisco, has composed eight operas and is usually performing with some of the world’s greatest singers, such as Renée Fleming, Ailyn Pérez, Patti LuPone and Audra McDonald. But when asked to visit Baton Rouge, his response was immediate.

“This is about working with local musicians, and that’s so meaningful to me,” says Heggie, 54. “And I’m beaming, because I’m so proud of Evan. We met two years ago at Songfest in Los Angeles, and I am so proud when young musicians initiate a project that addresses the arts, politics and social justice through the arts in their communities. Evan is doing that, and I’m proud to be a part of it.”

And, Heggie adds, he would “do anything for Sister Helen. Her enthusiasm, her passion, her joy — we all fall in love when we meet her. She really walks the walk. She’s not a poser on any level.”

Heggie would learn this during his first conversation with the nun. He and Terrence McNally had joined forces to create an opera commissioned by the San Francisco Opera’s then-general director Lotfi Mansouri, who initially requested a comedy.

“They wanted something funny to welcome in the new millennium,” Heggie says. “Terrence McNally wasn’t having any of it.”

McNally is considered one of American theater’s most important playwrights, with the musicals “Kiss of the Spider Woman” and “Ragtime” and dramas “Love! Valour! Compassion” and “Master Class.”

“Terrence wanted a big American drama,” Heggie says. “So, we worked on ‘Dead Man Walking’ for a year, and it was a hit.”

The opera was Heggie’s first. At the time, he was a composer whose day job was manning the San Francisco Opera’s public relations office. Looking back, the whole idea almost seems preposterous.

“When I think about it now, I really had a lot of nerve writing something like that,” he says, laughing. “I’d never done anything like that before.”

Neither Heggie nor McNally consulted Prejean before starting the project.

“She heard about it, and I was surprised by her overwhelming enthusiasm,” says Heggie. “You develop these stereotypes of priests and nuns, and you realize they’re all preconceived notions. Sister Helen helped me get a sense of who she is, which helped me in composing the opera.”

Heggie has since collaborated with Prejean on three song cycles, a set of related songs that form a single musical entity — “The Deepest Desire” in 2002, “Breaking Higher Ground: Bruce Springsteen Rocks New Orleans” in 2006 and “The Breaking Waves” in 2011. Songs from these compositions also will be performed in the Saturday program at LSU.

Prejean, 76, gained worldwide notoriety as an advocate for abolition of the death penalty after an acquaintance asked her to correspond with a convicted murderer at the Louisiana State Penitentiary at Angola.

She became spiritual adviser to convicted murderer and rapist Elmo Patrick Sonnier and later to convicted murderer and rapist Robert Lee Willie. She recounts both experiences in “Dead Man Walking.” She’s since advocated for others, most recently condemned Boston Marathon bomber Dzhokhar Tsarnaev.

The opera, as does Prejean’s book and Robbins’ film, makes clear that the condemned are on death row for a reason.

“We placed the crime at the beginning, so everyone knows he’s guilty,” Heggie says. “There’s no doubt, and the opera takes no sides on the issue. You know what happened and what the characters believe, and it’s left up to the audience to decide.”

Even Heggie had difficulty with the subject at first, not sure he wanted to deal with a story that revolved around such a heinous crime. The opera alludes to Sonnier’s murders of 18-year-old Loretta Ann Bourque and her 17-year-old boyfriend, David LeBlanc, in 1977. Sonnier also was convicted of raping Bourque.

“There’s something about it; I was a little bit afraid to go there,” Heggie says. “The death penalty is confusing, and I didn’t want to feel sympathy for this heinous act.”

Heggie watched the film, but only once. Then he read Prejean’s book several times, circling and underlining important passages along the way. He also learned that she’s no ordinary nun.

“We follow her, knowing that the inmate is guilty but wondering where’s she’s going to take it,” he says. “Will there be redemption in the end?”

For Heggie, the ending resulted in friendship with this unconventional nun, who has invited him to dinner with her family and to tour the city when he arrives in Baton Rouge.