A guy, a girl, a guitar, and a movie that went on to gross 100 times its budget—that’s the formula for Once, a new musical about a Dublin busker and a Czech immigrant who fall quickly into harmony and slowly into love. Glen Hansard and Markéta Irglová, stars of the 2006 film, have supplied the music and lyrics, wordsmith Enda Walsh the book, John Tiffany the direction, and Steven Hoggett the movement. Although the show had once hoped to begin on Broadway, it will now launch with a trial run at New York Theatre Workshop with a local cast led by Steve Kazee and Cristin Milioti. With luck, they’ll take the chorus of the film’s Oscar-winning song to heart: “Falling slowly sing your melody/I’ll sing it loud.”

Tuesdays, Wednesdays, 7:30 p.m.; Thursdays, Fridays, 8 p.m.; Saturdays, 3 & 8 p.m.; Sundays, 2 & 7 p.m. Starts: Nov. 15. Continues through Jan. 15, 2011