CANNES, FRANCE -- On paper, Jacques Audiard's buzzed-about Cannes Film Festival entry “Emilia Perez” would not seem anything like a good idea for a movie.

The film, which premiered Saturday in Cannes, is probably the first movie that can sincerely be compared to both “Sicario” and “Mrs. Doubtfire" — and that's just a start.

Zoe Saldaña stars as Rita, a Mexico City lawyer hired by the cartel kingpin Manitas to help him flee Mexico for gender confirmation surgery. This turns out to be the beginning of a relationship that will continue between Rita and Emilia Perez (Karla Sofía Gascón). Emilia returns years later, posing as Manitas' sister, to stay close to her children who are living with her ex-wife (Selena Gomez).

Also, it's a musical.

As gonzo as its premise may be, or possibly because of it, “Emilia Perez” gave Cannes a mid-festival jolt. Though not every critic has swooned for its melodramatic grandeur, there was applause even after the film's press screening.

“It occurred to me as a kind of opera,” Audiard told reporters Sunday.

Audiard, the protean French filmmaker of “A Prophet,” “Rust and Bone” and the 2015 Cannes Palme d'Or winner “Dheepan,” said the idea first occurred to him while reading a novel with a chapter about a narco trafficker who wanted to change his identity. From that starting point, Audiard built a shifting narrative worthy of a telenovela.

“To get into this kind of film by Jacques, you have to be like Jacques, who’s a bit mad,” said Gascón, laughing.

While the film boasts a pair of well-known stars in Gomez and Saldaña, Gascón is the revelation of the movie. The 52-year-old Gascón, who is trans, plays both the ruthless Manitas, with a grill covering his teeth, and the benevolent, bubbly Emilia. The two roles have strikingly physical presences.

“It was difficult at first. I didn't want to play the part of Manitas. I only wanted to play the part of Emilia. It took several months for me to convince myself that I could do both,” said Gascón. “At one point, we didn't know who would be playing the two characters and then it became quite obvious that it would be me.”

Audacious as “Emilia Perez” may sound, it comes off remarkably sincerely. The film, pondering questions of personal change, follows Rita and Emilia across years and multiple countries. The songs are penned by French pop musician Camille; Clément Docul does the score; and Gomez gets a moment at the microphone at a karaoke bar.

Gascón on Sunday said she hoped Emilia would be seen as not just a trans character.

“Trans people should be treated like just anybody else. I'm not better or worse than anyone else. I think we should be taken for what we are,” said Gascón. “We have our body and we're allowed to change it because we want to.”

The narrative leaps and tonal juxtapositions of “Emilia Perez” may be a lot for some, but for Audiard, that was much of the attraction.

“Something shocks me deeply in Mexico — all these problems of missing people. There are whole regions you can’t go because they aren’t safe," said the director. "I wanted to make a musical. So why not against the background of a tragedy?”