Sharon Stone and Bernard-henri Lévy in Race for the White House

At the 2005 Venice Biennale, Italian artist Francesco Vezzoli caused a huge buzz with his hilarious Trailer for the Remake of Gore Vidal's Caligula.

A five-minute frenzy of outrageous images, it starred Vidal, Helen Mirren, Milla Jovovich, Benicio del Toro and Courtney Love as the mad Roman emperor. In another project, also shown at that Biennale, he created an entire TV program, a sort of Blind Date - only the women picking out the eager, competing young men were stars, including Catherine Deneuve, Marianne Faithfull and Jeanne Moreau.

This year he has gone further in the audacity of his spoof projects. He has, with the aid of real Washington political advisers, created two commercials for competing US presidential campaigns - pitting Sharon Stone against the media philosopher Bernard-Henri Lévy.

The work, called Democracy, is being shown as part of the official Italian pavilion It is set in a dark, circular room, its ceiling lined with red and blue helium balloons as for an election convention.

On one screen Stone, as candidate Patricia Hill, embraces servicemen, kisses black children and magisterially tosses her rather stubborn wig, a Condoleezza-meets-Hillary do.

On the other, Lévy, as candidate Patrick Hill, wearing a tie perhaps for the first time in his life, shakes hands with the Pope. The videos play cacophonously, such that the viewer hears snatches of cliche: "resist the Taliban"; "a strong and free America"; "a steady voice, a determined leader"; "voice of the people".

"With the dating show, Comizi di non Amore [a reference to the Pasolini film Comize di Amore], I contacted the biggest TV production company in Italy, and asked them to make the pilot; it was very professional," said Vezzoli. "With Caligula, I went to Hollywood, engaged a credible cast, and delivered the footage to people who make trailers for films like Spiderman. With Demokrazy I asked Mark MacKinnon of Public Strategies, who worked on the 2004 George Bush campaign and who is now working with Senator John McCain; and Jim Mulhall of Squier Knapp Dunn, who worked for Bill Clinton in 1996."

He makes this process sound simple, though it's hard to see how a 35-year-old Italian artist - even one who charmed Bianca Jagger into participating in a work when he was still a student at Central St Martin's in London - persuaded these high-powered Washington creatures to help with his project.

Vezzoli, who was born in Brescia, shruggged. "Once you've done many projects it is not hard to get an appointment with Sharon Stone; it's not even hard to get a yes.

"But it does become complicated when you get involved with the whole Hollywood machine, [but] ... to their great credit, neither Stone nor Lévy demanded to see the work before it was shown."

The political advisers, said Vezzoli, "made sure every outfit, every gesture was credible". They turned Stone into "Martha Stewart meets Laura Bush; they stripped her of all her glamor."

The work is about manipulation, about packaging; and, in its barefaced used of celebrity, said Vezzoli: "I am declaring my weaknesses. I am fascinated by celebrity culture, and repelled at the same time.

· La Biennale di Venezia is open to the public from tomorrow until November 21