"Have you been to the loo yet?" Lana Wachowski asks just before a special screening of "Cloud Atlas" at the Pickford Center for Motion Picture Study in Hollywood begins. As we just met two minutes ago, it's a question that feels just a touch personal. Really, though, she's just looking out for her guest's best interests.

"Cloud Atlas," the audacious, time-tripping, Big Idea movie Lana adapted and directed with her brother, Andy, and friendTom Tykwer, clocks in at a sprawling 2 hours and 52 minutes. And because the film feverishly hopscotches back and forth between its six interlocking stories, you leave your seat at your own peril, running the risk of missing of ... oh ... Hugh Grant licking blood off a knife as a cannibal or Hugo Weavingmaking a grand entrance as a female nurse who'd make Louise Fletcher's "Cuckoo's Nest" administrator cower.

The hugely ambitious "Atlas" adapts David Mitchell's 2004 rage-against-the-machine, Russian-doll-style novel and asks several actors, including Tom Hanks and Halle Berry, to play several roles in the film's ultimately optimistic tales of human struggle set in the past, present and distant future. It's as commercial as the Wachowskis' "Matrix" trilogy, but, in many ways, feels experimental too.

"The movie speaks a lot about human courage, and the producers obviously had a lot of courage, or stupidness, to get this thing produced,” Lana told the audience when the independently financed, $102-million "Cloud Atlas" premiered at the Toronto Film Festival last month.

As remarkable as the movie is, seeing the famously reclusive Wachowski siblings publicly promote "Atlas" is even more startling. Meeting the bald, barrel-chested Andy before the film screening Saturday in Hollywood, he notes that, before Toronto, their only other festival experience came at Frameline, San Francisco's gay and lesbian fest, with their debut effort, "Bound."

"The elation of the crowd at the Castro when the two women going off into the sunset was just incredible," he says, describing the closing moments of the 1996 crime thrillerstarring Jennifer Tilly and Gina Gershon.

"The response in Toronto was overwhelming too," adds the trans-gender Lana, who, until 2002, was known as Larry. "That ovation ... I was crying, I had to leave."

The Wachowskis seemed perfectly at ease negotiating well-wishers at a reception before the Pickford "Cloud Atlas" screening and, later, answering questions in a post-screening Q&A along with Tykwer, Mitchell and producer Grant Hill. Their reluctance to participate in promotional events over the years has nothing to do with social awkwardness. They simply place a high premium on privacy.

"This really isn't so bad," Lana says, her fuschia-and-red dreadlocks standing out in a sea of black-clad guests as she surveys the scene. "But there's a price that comes with the loss of anonymity. The ability to go out to a restaurant, to go to a bookstore. You can't put a price on that. It's precious."

So why this? Why now?

"There's a line in the movie, a line I wrote," says Lana, whose natural vivaciousness turns dead-serious for a moment as she quotes a piece of dialogue from late in "Cloud Atlas," a line spoken by a woman taking a stand for principle. "'If I had remained invisible, the truth would have remained hidden. I could not allow that.'"

"The timing just seemed right," Lana says. "Tom Tykwer inspired me. David Mitchell inspired me." She stops and smiles, again taking in the boisterous, pre-screening party at the Pickford. "The response to this movie has touched me in a deep place. I kind of feel like I've been waiting for this moment my whole life."