Historic Hollywood strikes have robbed the Venice Film Festival of some of its usual glitz as it launched its 80th edition Wednesday, but a raft of big-name -- and controversial -- directors are keeping the film world buzzing.

The world's longest-running film festival was due to start with "Challengers", a tennis romance with one of the biggest stars of her generation, Zendaya.

But it was replaced at the last minute by an Italian war drama, "Comandante", due to the ongoing strikes by Hollywood actors and writers -- primarily over pay and the threat of AI -- that has barred them from publicity work.

The rest of the line-up was largely unaffected: the festival will see Emma Stone as a Frankenstein-like creature in "Poor Things" and Bradley Cooper as legendary conductor and composer Leonard Bernstein in "Maestro", among several Oscar contenders.

But the strikes mean those stars will not be lighting up the red carpet.

Adam Driver has been given an exemption to show up for "Ferrari" on Thursday because the biopic by Michael Mann ("Heat") was made outside the studio system.

Jessica Chastain is also expected for the premiere of "Memory" at the end of the festival, according to Variety. It is her first outing since her Oscar-winning turn in "The Eyes of Tammy Faye".

- 'Apocalyptic ideas' -

All are competing for the top prize Golden Lion, to be awarded on September 9 by a jury led by Damien Chazelle, director of "La La Land".

He told AFP he understood the anxiety around AI -- which many fear could lead to computer-generated actors and scripts replacing humans -- but said some of the fears may be overblown.

"People have some apocalyptic ideas about it," said Chazelle a few hours before the festival opening. 

"I agree it's a major technological change like the internet or radio, and it will overturn a lot of things, but the art will survive."

Other attention-grabbing entries include Sofia Coppola's "Priscilla", about Elvis Presley's wife, and "The Killer" by David Fincher, who returns to the Lido two decades after "Fight Club" was famously booed at the festival only to become a cult hit later.

- 'Absolutely incomprehensible' -

But with less star gossip, a lot of attention risks being absorbed by the inclusion of Woody Allen with "Coup de Chance" (his 50th film and first in French) and Roman Polanski with "The Palace", both in the out-of-competition section.

Allen, 87, was investigated for an alleged assault on his adopted daughter in the 1990s. Though cleared by police, he has been effectively blackballed by Hollywood.

Festival director Alberto Barbera defended Allen's inclusion, telling AFP: "He has been completely absolved. Twenty-five years have passed and, for me, the hostility towards him, especially in the United States, is absolutely incomprehensible."

Polanski, 90, remains a fugitive from the United States over a conviction for raping a minor in the 1970s. The victim has long since forgiven him, but he faces other assault allegations.

The festival says he is not attending.

Barbera acknowledged it was more complex with Polanski but said: "The history of art is full of artists who were criminals, and we nonetheless continue to admire their work."

There are also out-of-competition premieres for a 40-minute Wes Anderson film, "The Wonderful Story of Henry Sugar", based on a Roald Dahl tale, and a new feature from indie favourite Richard Linklater, "Hit Man".

"The Caine Mutiny Court-Martial", the final film from William Friedkin ("The Exorcist"), who died this month at 87, is also playing out of competition.

er/fg