A STAR'S DOWN-TO-EARTH ROLE - by Linda Hales

Celebrities have worked for decades for such causes as global poverty and curbing the spread of AIDS -- staging concerts, speaking at hearings, generating donations. But there's no script for swaying public opinion in the elite domain of architecture.

Brad Pitt, though, has passionate interest in his favor.

"I'm an architectural junkie," the actor explains, "like the screaming girl in the crowd."

Pitt is speaking by phone from New Orleans, where he has presided over a summer-long architectural contest to create eco-friendly housing. (The winning entry, by two New York architects, looks like a smart solution to a widespread problem, although it's no swirl of cutting-edge aesthetics.)

The contest was the actor's idea, says Matt Petersen, director of Global Green, Pitt's partner in the New Orleans competition. Pitt has been frustrated over the slow pace of reconstruction in the Gulf region.

"I don't understand why it's taking so long," Pitt says. "We have a real opportunity to turn this catastrophe into something better. It's a real issue of justice.

"We're out there in the world trying to sell democracy, and we can't take care of our own. It's embarrassing."

By adopting a neighborhood -- Holy Cross in the Ninth Ward -- Pitt's hope is to jump-start the rebuilding process while providing a new standard for architecture that would give the rebuilt city a reputation for forward-thinking design and energy efficiency.

The contest's jury included such experts as the Pritzker Architecture Prize winner Thom Mayne. The winning project, called GREEN.O.LA by Andrew Kotchen and Matthew Berman of Workshop/APD, offered the most potential for adapting to various settings.

Pitt attributes his interest in architecture to a college course about Frank Lloyd Wright. (A picture of Fallingwater, the Pennsylvania house that Wright famously cantilevered over a brook, "really blew my mind," he says. It proved that people didn't have to "live in a box.")

More recently, he has been taken by the work of Frank Gehry, whose titanium-clad Guggenheim Bilbao museum in Spain moved Pitt to tears, he says. (He describes Gehry as a "friend and mentor" but clarifies that a widely repeated story of an apprenticeship at the architect's studio is "officially incorrect.")

The actor says he is inspired by a walk through a beautiful building. By extension, he can see how a thoughtfully designed community center and apartment building -- with geothermal heating, recycled rainwater and trellises for shade -- could become a healing element for residents.

Pitt has dabbled in architecture, although he says he's "very opinionated" rather than skilled. He remodeled his 1930s Arts and Crafts-style residence extensively. Designers at the Los Angeles office of the Graft architecture firm say Pitt collaborated on every detail of the guest house and stark art studio they completed (and show on their Web site, http://www.graftlab.com/ ). A shoebox of concrete, Venetian plaster and glass contains little more than a Gerrit Rietveld Zig-Zag chair, which can be hidden away in a wall. Pivoting glass doors offer a smidgen of eco-design by admitting breezes and keeping the need for air conditioning to a minimum.

The actor has also taken up the cause against global warming. "There's a ticking clock on this thing," he says. "Can you picture a world where our cars, where ourselves don't poison our environment?"

He couldn't resist adding, "I would certainly admire a president who said, 'We've got 10 years -- let's fix it.' "

Conquering mythic Troy might be easier, but Pitt has the platform -- though not yet the broad audience that a screen superstar is used to commanding.

"I've never been invited to Capitol Hill," he says.

Pitt's conversion to sustainable design has picked up steam since the remodeling.

According to Petersen, Pitt acted to offset carbon emissions by planting trees -- before such "carbon-neutral" gestures became popular in celebrity circles. By the time Pitt showed up last year at Bill Clinton's global initiative on climate change, the actor was already "pretty educated on the issues," Petersen says. He combined that knowledge with his understanding of passive solar architecture and began telling colleagues, "If we don't change things, we're going to consume ourselves out of existence."

Pitt owns two Priuses, though he says he spends more time on a bike. He apologizes for a gas-guzzling Range Rover acquired "for the kids," and says he's looking for an alternative vehicle. He's excited about hydrogen fuel cells and admires fellow actor George Clooney for owning an electric car.

Pitt is bothered by the idea that the battery used to power the electric car hasn't evolved since the turn of the last century.

"We need to get more people on the drawing board," he says. "There's all this energy out there to be harnessed. Let's get the energy count down to zero."

Pitt says he will return to New Orleans in December, while filming "The Curious Case of Benjamin Button." He intends to monitor progress.

"It's one thing to get them on paper," he says. "We need to build them."