The premiere of “Burn After Reading”, a comedy starring Brad Pitt and George Clooney, ensured an upbeat opening to this year's Venice film festival yesterday.

In the madcap movie by the Coen brothers, two Washington gym employees get caught up in the cloak-and-dagger world of international espionage, with results both daft and deadly.

It brings A-list star power and crowds of screaming fans to the 11-day event in the canal city, where Asian and European art house cinema is up against Hollywood heavyweights in the race for prizes at the closing ceremony on Sept 6.

The film re-unites Joel and Ethan Coen with actress Frances McDormand, who is married to Joel and who won an Oscar for her role in their 1996 film "Fargo." She also previously starred with Clooney, in “O Brother, Where Art Thou?.”

Clooney, by his own admission, regularly plays the fool for the brothers, who triumphed at this year's Oscars with “No Country For Old Men” which picked up four awards, including best picture and best director.

"I've done three films with them and they call it my trilogy of idiots," the actor told reporters after a press screening.

The 47-year-old plays a nervous, twitchy federal marshal whose extra-marital affairs bring him into contact with a gym instructor, played by Pitt, desperately seeking to extort money from a sacked CIA analyst whose memoirs go missing.

"After reading the part, which they said was hand-written for myself, I was not sure if I should be flattered or insulted," said Pitt, whose character the directors describe as a "knucklehead".

Joel Coen said he and his brother had "a long history" of writing parts for idiotic characters.

Although there are five US films in the main competition lineup of 21, they represent "independent" cinema as opposed to the big studios, which are not in Venice this time around.

Festival director Marco Mueller brushed aside concerns that Venice, which faces competition from the Toronto film festival starting next month, was struggling to secure top titles.

He said the lighter Hollywood studio presence was partly down to the writers' strike that ended in February, and added: "American cinema is very much at the centre of the program."

“Burn After Reading” is not in competition, but US films in the main lineup include “Rachel Getting Married,” directed by Oscar-winner Jonathan Demme and starring Anne Hathaway and Debra Winger.

Kathryn Bigelow directs Iraqi drama “The Hurt Locker,” a year after Brian De Palma's “Redacted” stunned audiences in Venice with its brutal reconstruction of events from the war.

Mickey Rourke stars in Darren Aronofsky's “The Wrestler” while acclaimed Mexican screenwriter Guillermo Arriaga makes his directorial debut with “The Burning Plain” starring Oscar winners Charlize Theron and Kim Basinger.