John Carney’s Once, from his own screenplay, has been around for a while as a beneficiary of rapturous reviews ever since this year’s Sundance Film Festival, where it won the World Cinema Audience Award. It richly deserves an even longer and wider run than it has received so far locally. I finally caught up with this truly magical Irish musical as a passive participant in the Ninth Provincetown International Film Festival, at which Kathleen Turner received a long overdue Lifetime Achievement Award, after being introduced and interviewed in a lively and informative Q&A by film scholar Molly Haskell.

Mr. Carney has ruefully described his 17-day shoot on hi-definition video as an “art-house musical,” possibly anticipating some difficulties in attracting audiences to a no-name attraction. It would be more accurate to describe this wondrously affecting achievement as a musician’s musical. Cillian Murphy was originally slated to play the lead role of the Dublin street busker who encounters a Czech singer-pianist immigrant eventually played by Markéta Irglová, a newcomer to the acting profession. When Mr. Murphy dropped out of the project, Mr. Carney decided to use Glen Hansard, who’d performed with Mr. Carney in the Irish rock group the Frames. It was then Mr. Hansard who recommended the then-19-year-old Czech pianist with whom he’d played a few impromptu numbers on a tour in the Czech Republic. The happy end result is that Mr. Hansard and Ms. Irglová make beautiful music together on the screen both literally and figuratively. Don’t miss Once. It has to be seen and heard to be believed and enjoyed.