TORONTO -- Seeing a world premiere at the Toronto International Film Festival can be a unique and often surprising experience -- even for the actors in the movie.

"Almost Famous" actor Patrick Fugit has a small role in the new Gwyneth Paltrow-Mark Ruffalo dramedy "Thanks for Sharing," and says he was blown away when he saw the film for the first time over the weekend at the Ryerson Theatre.

"I was all focused on my (parts) and I just came in and shot that and that's all I knew about," the 29-year-old said in an interview.

"I was really, as a viewer, was able to invest in everything -- in the story in the characters in the story, in what was happening. And the payoffs at the end, I mean they meant a lot to me. That's hard to do a lot of times when you're in a film."

"Thanks for Sharing" stars Ruffalo as a recovering sex addict who strikes up a relationship with a neurotic cancer survivor (Paltrow). Tim Robbins plays the leader of a sexual addiction support group.

The film is the directorial debut of Stuart Blumberg, who was nominated for an Oscar for writing "The Kids Are All Right." He also co-wrote this film, and was relieved to hear the audience reaction.

Said the director: "It's always a wonderful experience when you can make people laugh and cry in the same movie, so I was very gratified to hear people enjoying the humour but also really getting into the serious moments as well."

"Thanks for Sharing" is due to hit theatres Nov. 1.