VENICE: Hollywood megastars Brad Pitt and George Clooney kick off this year's Venice film festival on Wednesday with the world premiere of the latest quirky offering from the Oscar-winning Coen brothers.

The festival, running through September 6, is set to bring a bevy of stars to one of the world's top cinema showcases, including Charlize Theron of South Africa and US star Kim Basinger, as well as new offerings by top filmmakers such as Takeshi Kitano and Jonathan Demme.

Kicking off the celebrations but shown out of competition, the Pitt-Clooney crime comedy "Burn After Reading" by 2008 Oscar-winning duo Joel and Ethan Coen also
stars John Malkovitch and Tilda Swinton.

In the film, the star pair play two middle-aged gym employees who stumble on the memoirs of a retired CIA agent and try to sell the manuscript to finance cosmetic surgery.

Oscar winners Theron and Basinger play in "The Burning Plain", Mexican-born screenwriter Guillermo Arriaga's first shot at directing.

Of the 52 films selected to screen at this year's Venice Mostra, 21 will be competing for the Golden Lion top prize, including the latest films of Japanese directors Kitano and
Hayao Miyasaki.

Both Kitano's "Achilles and the Tortoise" and Miyasaki's animated feature "Ponyo on the Cliff by the Sea" are tipped as favourites for the top prize.

Other strong runners include US director Darren Aronofsky's "The Wrestler", starring Mickey Rourke, and French filmmaker Barbet Schroeder's thriller set in Japan, "L'Inju:
La Bete dans l'Ombre" (The Beast in the Shadow).

Meanwhile "Silence of the Lambs" director Demme will present the much anticipated comedy "Rachel Getting Married", starring Anne Hathaway as a troubled young woman showing up at her estranged sister's wedding.

An African film in the running is "Teza" by US-based Ethiopian veteran Haile Gerima tracing the life of a young Ethiopian from his student days in West Germany in the 1970s
to his return to his native village at the age of 60.

From north Africa is Franco-Algerian cineaste Tariq Teguia's "Gabba" (Inland).

Veteran German director Wim Wenders, the man behind "Buena Vista Social Club" and "Paris, Texas", will head this year's jury, which includes Italian actress Valeria Golino, Argentine filmmaker Lucrecia Martel and Hong Kong's Johnnie To.

Among other films being shown out of competition are French director Claire Denis' "35 Rums", Iranian filmmaker Abbas Kiarostami's "Shirin" and an autobiographical documentary by Australian director Agnes Varda.

This year's event is the 65th Mostra. The festival, launched in 1932, was not staged during World War II, while several festivals were held without films in competition.