The film is one of 20 films in competition for the Film Festival's prestigious Palme d'Or.
American director Richard Kelly said Southland Tales was "meant to be experienced like a puzzle".
"I always thought that the film was going to push buttons and I think it's going to continue to," he added.
Gellar described the film, which also stars former wrestler The Rock, as "a step up" from Buffy and a "wonderful learning experience".
Sex - in many forms and, in at least one case, unsimulated - is heating up screens at the festival, confirming the event's reputation for taboo-busting fare.
Five films in the official competition alone have already offered enough nudity to mark them for mature audiences only, and one, Shortbus, by US director John Cameron Mitchell, blurred the boundary between pornography and art with its actors engaging in real intercourse.
Other movies featuring lots of skin include Summer Palace, a well-regarded Chinese contender for the Palme d'Or prize, the British flick Red Road, the revolting Taxidermia from Hungary, and the French movie Charlie Says.
Other sexed-up features are to be found in theatres outside the main selection, among them The Exterminating Angels by French director Jean-Claude Brisseau - who was convicted of sexual harassment last December for having two of his actresses masturbate for him during auditions - and Princess, a Danish animation that makes bloody judgement on the porn industry.
Thanks smh.com.au |
