Actor Paul Giamatti of "Cold Souls" poses for a portrait at the Gibson Guitar Lounge during the Sundance Film Festival in Park City, Utah, on Monday, Jan. 19, 2009. (THE ASSOCIATED PRESS/Mark Mainz)

TORONTO - U.S. actor Paul Giamatti says he's looking forward to tackling Mordecai Richler's cantankerous hero Barney Panofsky in a film adaptation of the Giller Prize-winning novel, "Barney's Version."

But the acclaimed actor says he's getting a bit trepidatious about taking on such a literary icon, noting the character holds particular sway in Italy, where the 1997 book was a bestseller.

"It's making me nervous," Giamatti said Tuesday from New York about the impending shoot, scheduled to begin Aug. 17 in Rome.

"I was like, 'Jesus, God, I'm going to trash this national treasure.' I hope I don't. What's funny is, apparently in Italy, it's even bigger, that book. It's huge...and that almost scares me more than Canada."

"Barney's Version" was a runaway hit in Italy, where the Montreal-born Richler was treated like a rock star when he visited the country on a book tour.

"They're a lot scarier, the Italians, they can get really out of hand. That's actually a little bit scarier to me," noted Giamatti, whose relatives are from Naples.

Kidding aside, Giamatti has already had great success portraying an iconic hero. His recent portrayal of the U.S. founding father John Adams for the HBO miniseries "John Adams" netted him a slew of acting accolades.

He joked that if he can handle the second U.S. president - portrayed by Giamatti as a bitter, difficult man - he can handle the ornery Barney Panofsky.

"I think this guy's actually a nicer person in some ways than that guy was," said Giamatti, who brings his latest film, "Cold Souls," to theatres this weekend.

"Barney's Version" tells the story of a bad-tempered, hard-drinking man who may have been responsible for his buddy's disappearance.

The cast includes Dustin Hoffman as Barney's foul-mouthed father, Izzy, and Minnie Driver, Rosamund Pike and Rachelle Lefevre as Barney's wives.

Filming is also set to take place in Montreal, the Laurentians and New York.

The big-screen version of "Barney's Version" comes from Canadian producer Robert Lantos, who said earlier this year that he spent 12 years working on a screenplay "worthy of Richler's magnificent book."

And for years, Lantos said he's imagined Giamatti in the role of Barney Panofsky.

"He is an actor of immense gifts and born to play this part. It will be a treat to watch him embody Barney," he said in a release

Giamatti, whose other films include "Cinderella Man," "Sideways" and "The Illusionist," said he'd never read Richler before joining the cast and is most intrigued by the aging his character will do in the film.

"He is cantankerous, but he's got a lot of sort of shadings within the cantankerousness. And he's a bastard in a lot of ways, but he's not in a lot of ways," said Giamatti.

"He's very contradictory, which is really nice. The progression of the aging is really nice, it's a lovely character. I get to do all different kind of things and it's a very subtle character.... I'm going to have a good time playing it."

The cast also includes Scott Speedman as Barney's best friend Boogie, and Bruce Greenwood as Blair, Barney's romantic rival.

The project is a co-production between Lantos's Serendipity Point Films, the Montreal-based Lyla Films and Fandango of Rome.

"Barney's Version" was Richler's 10th and final novel. He died in 2001.