Love Happy is a 1949 American musical comedy film, released by United Artists, directed by David Miller and starring the Marx Brothers (Groucho Marx, Harpo Marx and Chico Marx) in their 13th and final feature film, as well as a memorable walk-on by a relatively unknown Marilyn Monroe. The film, produced by former silent film star Mary Pickford, features Groucho Marx in a smaller role than usual, with a supporting cast including Ilona Massey, Vera-Ellen, Paul Valentine, Marion Hutton, Raymond Burr, Bruce Gordon (in his film debut), Eric Blore, and Marilyn Monroe in the aforementioned sequence with Groucho. The plot was written by Frank Tashlin and Mac Benoff, based on a story by Harpo. Plot Private detective Sam Grunion has been searching for the extremely valuable Royal Romanoff diamonds for eleven years, and his investigation leads him to a troupe of struggling performers, led by Mike Johnson, who are trying to put on a musical revue called Love Happy. Grunion notes that the impoverished young dancers would starve were it not for the sweet, silent Harpo, at Herbert & Herbert, a gourmet food shop that also trafficks in stolen diamonds. Harpo kindly helps ladies with their shopping bags, all the while pilfering their groceries and stuffing them in the pockets of his long trench coat. When the elegant Madame Egelichi arrives, store manager Lefty Throckmorton tells her that "the sardines" have come in. Harpo sneaks into the basement and watches as Lefty lovingly unpacks a sardine can marked with a Maltese cross, and swipes the can from Lefty's pocket, replacing it with an unmarked one. Madame Egelichi, who has gone through eight husbands in three months in her quest for the Romanoff diamonds, is furious when Lefty produces the wrong can. When Lefty remembers seeing Harpo in the basement, she orders him to call the police and offer a $1,000 reward for his capture. At the theater, meanwhile, unemployed entertainer Faustino the Great asks Mike for a job as a mind-reader, and when Faustino's clever improvisation stops the show's backer, Mr. Lyons, from repossessing the scenery, Mike gratefully hires him. Harpo, who is secretly in love with dancer Maggie Phillips, Mike's girl friend, gives her the sardine can, and she says she will eat them tomorrow. A policeman sees Harpo inside the theater and brings him to Madame Egelichi, who turns Harpo over to her henchmen, Alphonse and Hannibal Zoto.