Sarah Michelle Gellar

CANNES, France - Sarah Michelle Gellar is ever so happy to play a bubble-headed porn star in “Southland Tales,” the 160-minute dark, comic, American sci-fi fantasy that premiered last night at the Cannes Film Festival.

But when asked if she’d ever want to star in a real skin flick, Gellar quickly set the record straight: “No, thank you. I’ve lived out every odd fantasy and I’ve finished that chapter,” said the gal forever known as “Buffy, the Vampire Slayer.”

Whereupon her “Southland” co-star Dwayne “The Rock” Johnson chimed in, “I’ve made many. You might have seen them.”

The offbeat $15 million venture brought both stars to their first ever Cannes premiere. “It’s overwhelming, it’s exciting,” Gellar said. “I’ve been in this business a long time and it’s almost surreal to be here. It’s something other people do. I’m nervous about walking up the red carpet tonight. What if I trip?”

“We’re all going to laugh,” the Rock told her, adding, “It’s a dream come true to be here. There are a lot of actors out there who have tremendous success and never have a movie that’s selected for Cannes. I’m excited, I’m proud, I‘m thankful.”

In the follow-up to his cult hit “Donnie Darko,” “Southland” director Richard Kelly taunts Bush-era homeland security, America’s obsession with celebrity, and pervasive violence. The cast also includes Justin Timberlake and Seann William Scott.

But those themes obviously made some Cannes viewers uncomfortable, as many people walked out of the screening.

“It’s a film that needs to be experienced in more than one viewing,” Kelly said.