"Until I read the piece, and I was real upset," Pitt jokingly added.
Pitt's character, an ignoramus in way over his head on a blackmail scheme, is among a gaggle of boneheads caroming about in "Burn After Reading," whose cast includes his and the Coens' frequent collaborator George Clooney, plus John Malkovich, Tilda Swinton, Richard Jenkins and Joel Coen's wife, Frances McDormand.
Opening in theaters Friday, the movie casts Pitt and McDormand as fitness trainers who stumble on a disc containing classified documents and try to extort cash from the ex-CIA analyst (Malkovich) who was the origin of the leaked data.
Pitt plays the goof to the hilt, his character's inept attempts at cloak-and-dagger intrigue providing some of the movie's biggest laughs.
"The leading man role is usually the guy who's got the answers, figures things out and defuses the bomb within seconds and is always experienced. And all of that's pretty good for the ego sometimes. But it's more fun playing guys who make the wrong choices, have limited experience and make presumptions," Pitt said.
Wearing fitness club shorts and T-shirt, with his hair teased into a puffy tower with a blond streak, Pitt also toyed with his movie star looks in "Burn After Reading."
"We had kind of a competition going on the set as to who had the most ridiculous hair, and I think you may have won, Brad," co-star Swinton, whose character has a strange, swirled hairdo herself, said at a festival news conference alongside Pitt, the Coens and Malkovich.
"We were all going in for that Javier Bardem prize," Swinton said, referring to the odd page-boy hairdo Bardem wore in last year's Coen brothers crime thriller, "No Country for Old Men."
In an interview with The Associated Press a day earlier, the Coens said Pitt's hairdo was a happy accident. Ethan Coen said they had figured that as a gymnasium worker, the character might have a crew cut.
"Just by accident, Brad had done a commercial or photo shoot or something where his hair had been streaked, and he went in for a fitting for wardrobe for this with this kind of leftover hair, so we went, `Oh, how about that?"' Ethan Coen said.
Pitt has tended toward action and drama, including "The Curious Case of Benjamin Button," a tale due out late this year adapted from an F. Scott Fitzgerald story about a man who ages backward from old age toward infancy.
Aiming for laughs with "Burn After Reading" did not seem out of place to Pitt, though.
"I feel I've been doing comedies for years, but maybe they weren't so funny," Pitt said.
Pitt, who has worked with Clooney on "Ocean's Eleven" and its two sequels, was asked if he might work again with romantic partner Angelina Jolie. Their relationship began after they co-starred in the action hit "Mr. and Mrs. Smith."
"Angie and I, we're working together everyday, I can guarantee," Pitt said.