The 34-year-old singer revealed on Twitter that she wrote the music for Stewart's upcoming short film, Come Swim, which will be the actress' directorial debut. "I composed the soundtrack for Kristen Stewart's new short film Come Swim, which is also premiering at Sundance!" St. Vincent, whose real name is Annie Clark, tweeted on Wednesday.
Stewart, 26, has reportedly been dating the musician since early October, and was first spotted holding hands with her while walking around New York City. St. Vincent was last linked to supermodel Cara Delevingne, but the two reportedly split this past summer after dating for one year.