VENICE (Reuters) - Matt Damon stars as a whistleblower at a big U.S. agri-business company in "The Informant!," a black comedy based on a true story which had the audience laughing out loud at the Venice film festival.
Damon had to put on 30 pounds, wear a mustache and look unusually unglamorous to play Mark Whitacre, who turns from corporate golden boy at Archer Daniels Midland to FBI informant to uncover price-fixing practices in the industry.
"It was probably the funniest time I ever had working because I didn't have to think 'I have to go to the gym after work', and I just basically ate everything that I could see," Damon told reporters on Monday.
Dreaming of becoming a national hero and moving up the company ladder, Whitacre agrees to wear a wire and carry a hidden tape recorder to give the FBI the evidence it needs to incriminate his bosses.
But nothing is straightforward in Oscar-winning director Steven Soderbergh's film, which takes a farcical twist as it quickly becomes clear that Whitacre is not as well-meaning and reliable as he may seem.
"If you are not accustomed to lying you are invariably going to trip yourself up, which makes it fun to play this guy because he is never wrongfooted. And even if he is for a moment he then catches on until someone finally just says stop," Damon said.
Soderbergh, who already worked with Damon in his "Ocean's" trilogy, is not new to exposing corruption and corporate greed.
"Erin Brockovich," also based on a true story, was about a single mother taking on a water-polluting Californian company, while "Traffic" -- which won four Oscars -- looked at the drugs trade.
But in The Informant!, set in America's Midwest in the 1990s and premiering out of competition in Venice, he takes a distinctly lighter approach.
The film, on which Soderbergh started working in 2001, could be seen as making not-so-veiled references to recent U.S. corporate scandals, but he said that what really drew him to the story was Whitacre's bizarre personality -- and the reactions of those around him.
"It takes two people for a lie to work -- it takes the liar and somebody to believe it ... In this case for the lie to work you have the FBI agents ignoring so many signs that something is wrong because the case is so big," he said.
Unlike for previous films, Soderbergh did not want to meet the real Whitacre nor any of those involved in the story before shooting The Informant!, which is based on a book by Kurt Eichenwald.
"As we determined that the film was going to be a comedy, and a very subjective film ... my talking to the real people was not going to help me and it may hurt me," Soderbergh said.
"The strange thing is that Whitacre has seen the film and says that it's very accurate."
Editing by Paul Casciato