Emma Stone and director Yorgos Lanthimos brought audiences yet another hilarious and freaky film as "Kinds of Kindness" premiered in competition in Cannes on Friday.

The triptych, in which the same cast of actors recount three separate stories, was filmed as the Greek filmmaker put the final touches to his feminist Frankenstein remake "Poor Things" for which Stone won an Oscar.

Its occasionally repulsive scenes are balanced by dark humour, notably Willem Dafoe as a creepy guru in an orange speedo and one very shocking home movie that got big laughs at Cannes screenings.

"I thought it was funny and Emma thought it was funny, but we didn't know if people are going to find it funny," Lanthimos said before the premiere.

In early reviews, the Guardian called it a "macabre, absurdist triptych", while Variety called it a "quizzical concoction bound to baffle and delight".

Lanthimos said that, as trust grows between him and Stone, the duo has become "more bold and more brave".

- 'Big swing' -

The film was the latest hot ticket at the festival after Hollywood titan Francis Ford Coppola returned on Thursday to unveil his enormously hyped, wildly experimental and deeply divisive "Megalopolis".

The 85-year-old director's arrival at the world-famous movie festival -- where decades earlier he twice scooped the top prize Palme d'Or -- had been the talk of cafe terraces in the swanky Cote d'Azur city.

Would the epic $120-million project that he self-funded, and that has been gestating for some 40 years, be another masterpiece emerging from chaos, like "Apocalypse Now" all those decades ago? Or would the film that Coppola sold part of his California wine estate to create be a chaotic mess?

One early press screening attended by AFP was greeted with both jeering boos and enthusiastic applause.

Deadline hailed "a true modern masterwork of the kind that outrages with its sheer audacity," but The Guardian called the film "bloated, boring and bafflingly shallow."

The Hollywood Reporter said the film was "a staggeringly ambitious big swing, if nothing else," while The Times of London ripped into its "nails-along-the-blackboard performances, word-salad dialogue and ugly visuals".

- 'Moses and the prophets' -

"Megalopolis" is set in New Rome, a parallel and decayed version of modern-day New York filled with bacchanalian parties, crumbling ancient statues, and a Madison Square Garden that hosts chariot races and Greco-Roman wrestling bouts.

Coppola, one of Hollywood's most revered and mythologised directors, was greeted on the Croisette red carpet with a grand reception befitting an old master.

Straw hat and cane in hand, he entered the packed world premiere having promised a film of operatic scale.

He recently reeled off a list of influences that included Voltaire, Plato, Shakespeare, Hitchcock, Kubrick, Kurosawa, "Moses and the prophets all thrown in".

And, indeed, the movie is packed with endless quotes and references from the Ancient Classics to Enlightenment philosophers and modern novelists.

Dialogue flits from modern English to Shakespearean verse, and even Latin, and the drama is interspersed with archive footage ranging from the cosmos to Nazi rallies.

At one highly unorthodox moment, events on the screen interact with those in the real-life theatre.

- 'Bird' -

"Megalopolis" is one of 22 films competing for the Palme d'Or, facing a jury led by "Barbie" director Greta Gerwig, who will announce their verdict on May 25.

Also on Thursday, British director Andrea Arnold returned to Cannes with "Bird", the story of a 12-year-old girl navigating a world of domestic violence, teen pregnancies and broken families.

Channelling similar themes to her award-winning "Fish Tank", "Bird" adds fantastical, metaphorical and playful elements, including a flamboyant turn from Barry Keoghan ("Saltburn") as the girl's young father.

A day earlier "Wild Diamond" -- also about a fragile teenage girl, but this time one desperate to find fame on social media and reality TV -- was hailed by movie magazine Variety as "the arrival of a major filmmaker" in first-time French director Agathe Reidinger.

There were also great reviews for "The Girl with the Needle", a bleak period drama about a factory worker desperately trying to get an abortion -- with a murderous twist.

Still to come are a Donald Trump biopic, "The Apprentice", and new films from arthouse favourites David Cronenberg ("The Shrouds") and Italy's Paolo Sorrentino ("Parthenope").

Former Palme d'Or winner Jacques Audiard will present "Emilia Perez", billed as a musical about a Mexican cartel boss having a sex change, starring Selena Gomez.