"I don't know... E.T.?" actor Luke Kirby quipped last night when we asked him to cite his favorite onscreen love triangle of all time. The occasion was a special New York screening of director Sarah Polley's Take this Waltz, a film in which Kirby finds himself in just such a geometrical arrangement with Michelle Williams and Seth Rogen.

Beautiful, sad and colorful, the film is set over a summer in Toronto, which—through Polley's lens, at least—may be the most idyllic, charming place in Canada. "How much I wanted to live there," Williams said sweetly when we asked whether anything about Toronto had been surprising.

Friends including Genevieve Jones, Arden Wohl, and Kelly Choi joined for the screening, and two very special guests were spotted at the Sons of Essex's after-party: Polley's new baby, nestled against her chest; and Williams's boyfriend, Jason Segel.