Volkswacht Bodensee - Hollywood icons Costner and Demi Moore in Cannes comeback

The star-studded premieres arrive midway through the world's most famous movie festival, where "Emilia Perez" -- a musical about a transgender drug lord, starring Selena Gomez -- is currently the talk of the town.

Epic Western "Horizon, an American Saga" is a passion project for Costner, who told AFP he had started working on the screenplay in 1988.

Despite having enormous success with Westerns, including the Oscar-winning "Dances with Wolves", "Open Range" and television's "Yellowstone", he could not find a studio willing to fund his script.

"But I loved it and so I decided I would write four, which is very American of me -- insane," said Costner, who bankrolled the project himself.

The first film will premiere at Cannes on Sunday in a special screening outside the main Palme d'Or competition. A second film has also been shot, and both will launch globally in theatres this summer.

"Horizon" follows multiple characters and storylines on the violent frontier, as Europeans establish settlements on Native American land.

Costner stars along with Sienna Miller and Sam Worthington.

Another veteran US star, Demi Moore, takes centre stage in "The Substance", a horror film which tackles the immense pressures society places on women to achieve bodily perfection.

Moore starred in several hit movies in the 1990s, including "Ghost", "A Few Good Men", "Indecent Proposal" and "G.I. Jane".

But this year's Cannes is a remarkable return to the red carpet, after years in which Moore has made headlines more for her marriages to Bruce Willis and Ashton Kutcher than her acting.

- 'Schizophrenic' -

"The Substance" is among 22 films competing for the Cannes festival's top prize, the Palme d'Or.

High-profile entries that have played so far include Francis Ford Coppola's divisive epic "Megalopolis," Andrea Arnold's much-praised childhood saga "Bird" and Paul Schrader's widely panned "Oh, Canada".

The early frontrunner appears to be "Emilia Perez" from French auteur Jacques Audiard, who received a hero's welcome from the world's media as he hosted a press conference Sunday, a day after its world premiere.

Karla Sofia Gascon, a Spanish trans woman, stars as a Mexican drug baron who longs to change gender and escape the narco life.

"We're normal people who can have the careers they want," said Gascon.

Zoe Saldana plays a lawyer who must arrange the operation, which is kept secret from everyone including the narco boss's wife, portrayed by pop star-turned-actor Gomez.

The characters regularly break out into song, with lyrics tackling everything from plastic surgery to Mexico's struggles with corruption and warring drug gangs.

Audiard said he had originally envisioned the film as an opera.

The "crumbling of democracy" in Mexico, a country he finds to be "schizophrenic", provided the perfect setting for "a tragedy", said the director.

Outside of the Palme d'Or competition, Cate Blanchett launched "Rumours", which follows a group of world leaders who meet for a G7 summit but end up getting lost in a forest, with debauchery ensuing.

"I think if you try to make sense of this movie, you'll feel like you're losing your mind," joked Blanchett.

The Palme d'Or winner will be unveiled on Saturday, the festival's closing day.

C.Kreuzer--VB