 The film is largely based on the 1948 Broadway play, "The Silver  Whistle," rewritten as part of the Mr. Belvedere film series. The  film retains the names of nearly all the characters in the play but  the lead character is changed as Mr. Belvedere was not a character  in the play. The lead in the play was Oliver Erwenter, a romantic  hobo who wanders into the old folks home. The characters of  Erwenter and Belvedere are quite different although the plot is  essentially the same.