On behalf of himself and his fellow Americans, Ben Affleck is saying thank you to Canada.

Affleck made his latest return to the Toronto International Film Festival on Friday to premiere his Iran hostage thriller "Argo," for which he does double-duty as star and director.

Opening in theaters Oct. 12, "Argo" chronicles a joint effort by the CIA and the Canadian government to rescue six Americans from Tehran after the U.S. embassy was taken over by Islamist militants in 1978. While 52 others were held hostage at the embassy, the six Americans were hidden by Canadian authorities, who worked with U.S. operatives to concoct an elaborate scheme to get them out of the country.

"The idea they came up with was to pretend they were all on a location scout for a movie," Affleck said in a telephone interview before the festival. "They went to Hollywood and basically put together the back-story for a fake movie. They took out ads, did a read-through, all the real things a real movie would have to do."

Affleck stars as exfiltration specialist Tony Mendez, who teams with a Hollywood producer (Alan Arkin) to dream up a phony Canadian science-fiction flick they want to shoot in Iran, intending to smuggle the six Americans out as part of the film crew. "Argo" also features John Goodman and Bryan Cranston.

"It's really a movie about Canadian heroics and the relationship between Canada and America," Affleck said. "Once you see the movie, you'll see how it resonates, the theme of, 'Thank you, Canada.'"

Affleck has reason to give personal thanks to Canada. His bank-robbery hit "The Town" got a warm welcome from Toronto festival crowds two years ago, and he hopes for the same this time.

Along with "Argo," Affleck stars in a second Toronto festival film, Terrence Malick's romantic rumination "To the Wonder." Featuring Rachel McAdams, Javier Bardem and Olga Kurylenko, the film stars Affleck as an American whose relationship to a woman he met overseas turns cold, leaving him drifting back toward a childhood love.

Affleck had crossed paths with Malick over the years and showed him "The Town" while Malick was working on his family epic "The Tree of Life." Malick was casting "To the Wonder" at the time and offered Affleck the role.

"The Tree of Life" flowed from intimate domestic drama to images of the creation of the cosmos and the age of dinosaurs. Yet Affleck said that in "To the Wonder," Malick is "pushing it kind of further in an avant-garde direction. Even less linear. Though there are no dinosaurs, at least in the last cut that I saw."

Unlike the press-shy Malick, who skips interviews, premiere red carpets and other public appearances, Affleck will be on hand for the early screenings of "Argo." Nerve-wracking as it is to put a film in front of an audience, Affleck said he enjoys studying the crowd's response.

"I like to be part of it and be part of the ebb and flow of feeling an audience seeing it for the first time," Affleck said. "You do all this stuff in a vacuum, write the movie, rehearse it, shoot it. It's like being on stage without an audience. When the audience is finally there, I love to see how they react.

"It's exhilarating and it's satisfying and it's terrifying. Luckily, I'm always distracted by the sort of constant evaluation between my expectation of the audience's reaction and how they actually experience it. 'Oh, that didn't go over the way I thought it would. Why did they laugh there?' The terrible part is you start to want to recut it as you're watching it."