A Night at the Opera (film) DVD commentary. But this could not have occurred, because Sam Marx had died in 1933, during pre-production of "Duck Soup", two years before "A Night at the Opera" was released. The rumor arose because Frenchy had had such a cameo appearance in the Marx Brothers' earlier "Monkey Business". There is, however, a reference to the Marx Brothers' mother, Minnie Marx, during the stateroom scene, in which a woman asks, "Is my Aunt Minnie in here?" Part of the concept of casting the Marx Brothers as stowaways on a ship was recycled from "Monkey Business". As Groucho's and Margaret Dumont's characters
Monkey Business (1931 film) four stowaways because he can hear them singing "Sweet Adeline".) If so, it would be one of only a few times Harpo used speech on screen, as opposed to other vocalizations such as whistling or sneezing. At least one other possible on-screen utterance occurs in the film "A Day at the Races" (1937), in which Groucho, Chico, and Harpo are heard singing "Down by the Old Mill Stream" in three-part harmony. This was the first Marx film to be written specifically for film, and the first shot in Hollywood. Their first two films were filmed at Paramount Pictures' Astoria Studios