In Emilia Pérez, French director Jacques Audiard boldly presents the tale of cartel boss Manitas del Monte who decides to retire from business and undergo gender reassignment surgery to become the titular character. Adding to the uniqueness of the film’s plot, Audiard tells the story via musical numbers that are as genre-bending and defying as the musical drama itself.

The two-hour film, starring Zoe Saldaña (Rita), Selena Gomez (Jessi) and breakout star Karla Sofía Gascón (Manitas del Monte/Emilia), is musically diverse, with rock, pop and rap leading musical numbers — all sung in Spanish — that are interwoven with the script as they capture the evolution and transformation of the aforementioned women, who are intrinsically involved in each others lives.

Manitas first hires fierce lawyer Rita to help facilitate her surgery, and years later, rehires her to help her reunite with wife Jessi, a rebellious woman at heart. Throughout the movie, all three have compelling musical numbers that add insight into their independent struggles as women in a chaotic country like Mexico that is riddled with narco violence, machismo and corruption.

“The goal was that the music and the songs were linked to the story and deal with emotions,” composer Clément Ducol, who alongside singer-songwriter Camille crafted the musical’s score, tells Billboard. “That it wasn’t only music reflecting the story but the music was the story.”

The French composing duo was involved with the project even before the script was finished. What they initially received from Audiard was a 20-page treatment, and they were hooked immediately. “I like [Audiard’s] work because it’s very raw and I knew it was going to be interesting working and singing in this project,” says Camille. “I knew he would go for something very natural and break the codes of a musical. I believed in Emilia Perez from the start.”

The songs were all written in Spanish with the help of language consultants, including Karla Aviles and Ignacio Chávez. “They really helped me understand the cultural references and particularities,” Camille adds.

Below, Ducol and Camille speak to Billboard about the music behind Emilia Pérez, out now in select U.S. theaters and premiering Nov. 13 on Netflix.

What was it about the project that made you want to be part of it?

Clément Ducol: Meeting Jacques Audiard was already an event because he is one of the most well-known directors in France. When he comes to me with the idea to make a musical, it was incredible. What was exciting was that Jacques invited us to be part of it since the very beginning. We actually didn’t have a script yet — only a treatment, like 20 pages of a novel. Everything was built along with the songs.

Camille: I’ve always loved Jacques’ work because it’s very raw, and I knew he would go for something very natural and break the codes of a musical. Reading the treatment, it really immediately struck me as something Shakespearean. I believed in Emilia Perez from the start.

Because music is very much a protagonist, I’m curious to know how you all landed on that vision and what were those early conversations like with the director?

Ducol: We were reading the treatment and would point out scenes that could be turned to songs. The goal was that the music and the songs were linked to the story and deal with emotions. That it wasn’t only music reflecting the story but the music was the story. The music shifts along with characters. It’s a story of emancipation, transformation and evolution so the music embodies all of that.

Camille: Jacques comes with questions. He doesn’t come with preconceived ideas. We’ve been with him questioning the script, the songs, the story, the characters. It was like back and forth process. A song like “Por Casualidad,” it changed three times not only because the song wasn’t good enough or needed more depth or to be enriched, it changed because the script changed to reflect what was at stake at that point. It’s a turning point in London when Emilia has made her transition and Rita has become a well-known lawyer. First we thought the song would be about them looking back on these years. And then we thought it should be about Emilia presenting herself as a new person to Rita. And Jacques said, “No, Rita is scared in this scene and we need to add suspense to the song. They’re not just friends catching up. This is where their friendship starts.” There’s many layers to this song.

The musical numbers are all in Spanish. How was that process of writing the lyrics? Did you write first in French then translate to Spanish?

Camille: I wrote the lyrics for the songs. Sometimes I imagined the lyrics in French, then I would switch to Spanish very quickly because I needed to hear how it actually sounded. As a lyricist, I’m looking for something that sounds good and right. I’m looking for a song that is a delight for the singers and the cast, whether a song is sad or happy. And for that, I needed to sing the words myself. There’s no point in writing in French and translating. It has to be in the language because the lyrics talk about the country, the reality, the landscapes, the people. We must say that this film is about transition, women changing, about Mexico, politics and compassion. I want to mention Karla Aviles, who is Mexican and who was our language consultant and really helped me understand cultural references and particularities. Ignacio Chávez too. We got feedback from them and it really was accurate and fair.

The music is stylistically versatile, there’s pop, rock, rap — what was your inspiration for the music?

Ducol: The inspiration was only the story and characters, it was a very intuitive process. There weren’t pre-existing ideas of what could be used, no styles were pre-determined. Jacques likes to say that music is trans-genre too, not only Emilia. As the music shifts along with the transformation of the characters, obviously there are a lot of different genres.

There are two musical numbers I’d love to break down. First “El Mal” by Zoe Saldaña, where she raps about corruption, and then the music transitions into a heavy rock song. How did you craft this musical number?

Ducol: Sometimes there were many steps because we had a pre-production process and Camille was doing the vocals, sometimes dialogue. Then we met the actresses and that was a new step for us. Sometimes the actresses gave us the right arrangement for the music. It changed a lot. For “El Mal” with Zoe, there was already this kind of rap, rock, opera but with an arrangement more electronic. And when Zoe sang the song and performed and danced, Jacques was at the studio and said we needed something more acoustic and rough. We redid the song with a live rock band.

Camille: We were lucky to have Zoe because she has a super rhythmical and sharp voice. She’s the character as we imagined her to be. She’s rapper, rocker, goes for it and Zoe was perfect.

There’s also “Mi Camino” by Selena Gomez. She was very in her element as pop star performing this song.

Ducol: We had written the bedroom scene for her, like walls turning into a techno song, something very punk. We had another song even punkier than this one and very rebellious. The first one was more like she wanted to rebel and second one was “I’m rebelling.” We hadn’t met Selena yet at that point and when Jacques met Selena he told us, “unfortunately we have to write another song. Help me find the song that tells the story of her as a woman and not only as the actress.” It was interesting approach. He wanted her to be revealed.

Camille: Selena has that quality. In her documentary we saw it too. She doesn’t talk about herself that much but you can feel she’s not hiding either. She’s not her vulnerabilities and that’s very inspiring for songwriters. She makes herself vey available to the character, to the director and us. She listens a lot to what’s needed. She gave that natural quality that she has, very round, milky and velvety voice and it deepened the character. The character of Jessi at the beginning was a little hysterical, stuck in her world, like a puppet. And Selena gave her something maternal, something central and now the character stands out a lot. In “Mi Camino,” she’s out of the box, she’s in love, she gains self-esteem and I think Selena really related to that.

Some have described the musical as a narcocorrido, do you agree with that?

Camille: I think Jacques wanted music to be incorporated because he had the intuition that songs and music would make this unbelievable story believable. Like an opera or musical drama. He presented it more as an opera because it’s a tale and singing allows characters to tell the truth about themselves and the truth about the world.

Ducol: We didn’t want to make Mexican music because we are not Mexican, we needed to be very connected to the story and characters, and there was no clear inspiration on Mexican corridos or folk music. For us, the Mexican identity of the music is more with the language and with the distinctive sounds of Mexico City.

Camille: Our goal as artists isn’t to say, “This is what it is.” Everyone will have their own opinion or perspective.