Hollywood stars jetted into Cannes on Tuesday as the world's most famous film festival gets under way in dramatic circumstances, including a fugitive director's daring escape from Iran, and a looming cloud of fresh #MeToo allegations. 

The festival officially kicks off in the evening with an honorary award for Meryl Streep -- just one of a host of international A-listers flocking to the sun-drenched Cote d'Azur, where legendary directors George Lucas and Francis Ford Coppola top the VIP guest list.

Coppola's decades-in-the-making epic "Megalopolis," an Ancient Rome-inspired saga set in a corrupt modern-day city, is the most anticipated of this year's entries for the top prize Palme d'Or.

"Cannes is important to him and he is important to Cannes. He comes as an artist," said festival head Thierry Fremaux, praising the 85-year-old director of "The Godfather".

"Megalopolis" is one of 22 films competing for the affections of a jury led by "Barbie" director Greta Gerwig.

Richard Gere will star in Paul Schrader's "Oh Canada", recent Oscar winner Emma Stone reunites with Yorgos Lanthimos in "Kinds of Kindness", and Demi Moore tries her hand at horror in "The Substance".

Outside the race for the Palme d'Or, George Miller's latest "Mad Max" instalment, "Furiosa", will get its world premiere on Wednesday, while Kevin Costner returns to the Western genre with "Horizon, an American Saga".

But darker, off-screen plotlines have emerged on the eve of the festival's 77th edition.

In a last-minute twist, director Mohammad Rasoulof -- also competing for the Palme d'Or -- announced on Monday he had escaped in secret from Iran, just days after being sentenced to eight years in prison on security offences. 

Rasoulof had been under pressure from Iranian authorities to withdraw his latest film, "The Seed of the Sacred Fig", from Cannes.

"I am grateful to my friends, acquaintances, and people who kindly, selflessly, and sometimes by risking their lives, helped me get out of the border and reach a safe place on the difficult and long path of this journey," he wrote on Instagram.

Rasoulof's lawyer Babak Paknia told AFP that the director plans to attend the festival for the premiere next week.

'Festive moment'

Meanwhile, France's film industry is in the midst of a belated #MeToo reckoning, with a string of accusations against its biggest star, Gerard Depardieu, and rumours in the run-up to Cannes of more accusations to come against high-profile figures.

Actor Judith Godreche, who has accused two directors of assaulting her when she was a teenager, is presenting a short film, "Moi Aussi" (Me Too) aimed at encouraging more women to come forward. 

On Monday, nine women accused Alain Sarde, a major French film producer, of having raped or sexually assaulted them.

His lawyer did not respond immediately to the allegations, which were published by ELLE magazine.

Camille Cottin, star of hit television series "Call My Agent!" and an outspoken feminist, will host this year's festival. 

She said there were a lot of issues she would like to address in her opening speech.

"But it's also supposed to be a festive moment... and I've only got four minutes," she told AFP.

Adding to the off-screen drama, a group of festival employees have called for a strike over pay and conditions that could cause disruption at the event. 

Festival head Fremaux insisted the focus this year will be squarely on the movies.

"No controversies come from the festival," he told reporters. "We have taken care to ensure the main reason we're all here is cinema." 

Trump, Coppola, Stone

Among the other entries for the Palme d'Or is "The Apprentice" -- a biopic of Trump's formative years from Iranian-born director Ali Abbasi. It stars Sebastian Stan, known for playing the Winter Soldier in Marvel films. 

And "Emilia Perez" has quite the synopsis: a musical about a Mexican cartel boss undergoing a sex change to escape the authorities, directed by France's own Golden Palm winner Jacques Audiard. Pop superstar Selena Gomez appears in a supporting role. 

But the hot ticket is undoubtedly Coppola's "Megalopolis", starring Adam Driver, on Thursday. 

There is a growing anticipation over whether the veteran director -- who self-funded the lavish epic -- can match his masterpieces of the 1970s, when he twice won the Palme d'Or for "Apocalypse Now" and "The Conversation". 

Film fans are also excited for new works from body-horror maestro David Cronenberg ("The Shrouds"), Italy's Paolo Sorrentino ("Parthenope") and Oliver Stone ("Lula", a documentary about Brazil's president). 

Playing out of competition is "She's Got No Name", one of China's biggest-ever productions, which features megastar Ziyi Zhang tackling the highly sensitive topic of women's rights. 

Legendary Japanese animators Studio Ghibli -- makers of "Spirited Away", "My Neighbour Totoro" and "Howl's Moving Castle" -- will receive an honorary Palme d'Or, the first offered to a group. 

And the festival will round off on 25 May with a final honorary award for "Star Wars" creator George Lucas.