Unfortunately, his first film, Las Vegas nights, was a disaster. “A picture like that can come back and haunt you” admitted the film’s star, Bert Wheeler. Still, its place in history is assured as the first film appearance by Dorsey, Buddy Rich, and—as an uncredited chorus member—Frank Sinatra.
This according to “The Dorsey brothers: Filmdom’s favorites” by Robert L. Stockdale (The IAJRC journal XLI/2 [May 2008] pp. 46–57).
Today is Tommy Dorsey’s 110th birthday! Above, a still from Las Vegas nights showing Sinatra, far right in the back row (click to enlarge); below, an instrumental piece from the film.