“Emilia Pérez” is not what most would conjure when thinking of a movie musical. And therein lies its superpower. Its writer-director, Jacques Audiard, chose to tell the story of a brutal Mexican drug cartel lord (played by Karla Sofía Gascón) who undergoes profound changes in midlife — including gender-reassignment surgery — as a romantic, comic, musical drama that doesn’t shy from its dark themes and social commentary.

Winner of the Cannes jury prize, soundtrack award and actress awards (shared by Gascón, Zoe Saldaña, Selena Gomez and Adriana Paz), it’s unexpected at every turn, with personal growth here and real menace there, requiring many different kinds of original songs. That’s where composers Clément Ducol and Camille Dalmais — better known as singer-songwriter Camille — came in. They crafted a suite of songs in a spectrum of genres, including two that demonstrate the film’s range: the self-actualization pop ballad “Mi Camino,” performed by Gomez, as the wife of the cartel boss, via karaoke; and the showstopping, rock-rap denunciation of poisonous hypocrisy, “El Mal,” in which Saldaña (with an assist from Gascón) blows up the screen.

Audiard originally wrote “Emilia Pérez” as an opera libretto (inspired by Boris Razon’s novel “Écoute”), but when it came to the screenplay, he was all ears. “Jacques didn’t want to work with a script that was already fully fledged,” Ducol says. “He gave us 30 pages of a tre.