TORONTO -- The first question that came to actress Zoe Kazan's mind when she read the script for "The F Word" was one many film-goers will no doubt have as well.

"I was just interested in, how does the guy who made 'Goon' make a romantic comedy? What does that look like?"' the New York-based star said in an interview at the Toronto International Film Festival, where "The F Word" is making its world premiere to wide praise.

That's not to say Kazan doubted whether director Michael Dowse -- of the aforementioned raucous hockey-bruiser tale and the "Fubar" hoser comedy franchise -- could successfully tackle a more love-centric story.

In fact, she was excited by the idea that the project that also stars Daniel Radcliffe might contain the same biting, masculine sensibility Dowse is known for.

"I think that sometimes these kinds of movies, romantic comedies, can be a little girly or a little mushy, and I knew he wouldn't make a movie that was like that," said Kazan, 30, who wrote, directed and starred in last year's romantic dramedy "Ruby Sparks."

"I know how funny he is and how sharp, and if you've ever met him, he's like a gigantic dude, and I think that that's a really cool thing -- to have a juxtaposition to a romantic movie. So that was a huge draw."

Filled with heart, humour and edge, "The F Word" stars Kazan as Chantry, a Toronto animator who develops a close friendship with medical school dropout Wallace, played by Radcliffe. Chantry lives with her boyfriend, Ben (Rafe Spall) and doesn't know that Wallace secretly holds a torch for her.

Toronto-based Elan Mastai wrote the charming story that also features Megan Park as Chantry's frank-talking sister, "Girls" series star Adam Driver as her idiosyncratic cousin, Allan, and Mackenzie Davis as a girl Allan develops an intense relationship with.

Kazan found Mastai's script to be "just excellent, so sharp, so on-point, so true to the way that men and women do interact."

"And then Dan Radcliffe is someone who I think is just immensely talented," she said. "I'd heard nothing but amazing things about him and I had met him once. We had a drink and I had just sort of thought how smart and funny he was, and that those qualities, the kind of lighter qualities we hadn't really seen onscreen before.

"So I was excited to play with him and draw some of that out."

Mastai said the "Harry Potter" star -- who also has two other films at the Toronto festival -- called them and thought the part was right for him.

"And of course, I think like most people, we were like, 'Well, is Daniel Radcliffe funny?' And it turns out, thankfully, he's actually hilarious. And when you meet him, he's this incredibly self-effacing, witty dry, grounded, guy.

"We realized if we could just capture what he's like just hanging out with him casually on camera, we'd have something really special."

And that's exactly what Dowse did.

"I just tried to let the actors live in the frame in two shots and tried to let the performances ring true rather than try to build the moment with the editing," said Dowse, who comes from an editing background.

"So that was one of the main challenges, is constructing the shoot so that we were given the time to let the actors work, and also have confidence in letting the whole scene play."

As for the challenge of taking on matters of the heart with a sweeter sensibility than what he's used to, Dowse didn't hesitate.

"The script is really well written and I was looking to do something different after I did 'Goon,' was trying to branch out and flex different muscles as a director," said the Montreal-based filmmaker, who co-wrote "The Grand Seduction" that's also at the fest.

"When I read the script, I loved how it really used comedy to build the romance in a way that we do in real life."

The Toronto International Film Festival runs through Sunday.

With files from Canadian Press reporter Cassandra Szklarski