Actor Paul Giamatti and producer Robert Lantos said the pressure was formidable when they took on the task of adapting beloved Canadian novel "Barney's Version" for the screen.

But listening to Florence Richler's reviews, they have nothing to worry about. The widow of "Barney's Version" author Mordecai Richler said she liked the film so much she's already seen it twice, and plans on seeing it again and again.

"I shed copious tears the first time," she told Canada AM co-host Seamus O'Regan in an interview on Monday. "Perhaps fewer last night (when it screened at the Toronto International Film Festival), but shamefully a great number."

Giamatti said he relished playing a bastard, but that he initially felt more pressure portraying Canadian literary hero Barney Panofsky than any role he's tackled.

"He's a figure who's so deeply imbedded in the culture and it's such a Canadian story," Giamatti told a press conference in Toronto on Sunday.

"And I'm like: 'And you hired a guy from Connecticut to come up and blow the whole thing, potentially?"'

Giamatti's no stranger to playing writers, having taken on the role of Harvey Pekar in 2003's "American Splendor." His performance in that film wasn't just an imitation of the cantankerous graphic novel writer, but an artful interpretation -- an inventive spin akin to a master jazz artist's cover of a classic.

For "Barney's Version," Giamatti said he relied on video footage and photographs of author Richler to find inspiration for Barney, often cited as Mordecai Richler's own cantankerous, hard-drinking alter ego –- a Montreal TV producer who may also be a murderer.

"There are great pictures of him sort of shuffling down the street and sitting at a bar and smoking a cigar," said Giamatti. "It was like, 'This guy looks really cool, I could play this guy."'

Florence Richler said Giamatti far from blew it, calling his performance "extraordinary."

"He was overwhelming in this, such an emotional man, and so true," she told Canada AM.

In their non-fictional lives, Florence Richler (nee Wood) was a Dior model when she met Mordecai Richler in London. They married in 1960 and had five children.

She was always the first to edit her husband's drafts before he sent them off to his editors.

She pointed out the film was moving not because it was autobiographical -- but that it successfully captured the spirit of her husband's Giller prize-winning novel. And she didn't mind that details such as the location of her husband's gravesite were off.

"I think all fiction is a spinoff on reality, isn't it?"

When asked whether the character of Miriam Greenberg -- Barney's third and final wife -- bears any similarity to her, Richler replied, "There may be a touch."

"It was such a large palate that (director Richard J. Lewis) painted with," she said. "It touches each one of us, with all the sadness and the romance, all the disappointments in life."

"Do I sound partisan?" she asked, with a laugh.

"Barney's Version" the film also stars Minnie Driver, Rosamund Pike and Rachelle Lefevre – who play Barney's wives. The formidable cast also includes Dustin Hoffman as Barney's father Izzy and Scott Speedman as Barney's pal, Boogie.