Although Victor Herbert's music was used for this movie, the plot is not the same as that of the original musical, as was often the custom back then for adaptation of stage musicals. Many of the lyrics (by Rida Johnson Young) are also changed.
The two crucial missing characters are the Governor's effeminate son Etienne and the Gypsy girl with whom he has fallen in love. They form an alternate love match which was completely eliminated from the movie version.
Several modern sources, including American Film Institute of Feature Films 1931-40, include Marjorie Main in an uncredited role as a casquette girl, based on erroneous information provided by a former film historian. Marjorie Main does not appear in this film in any way, and the actress in question, properly identified in IMDb, is Margaret Bloodgood.
Although his name is never mentioned on screen, the pirate leader is called Bras Pique, and he is killed in the scene where the Captain's men attack the pirates. In the original operetta, his alter ego is the Lieutenant Governor's effeminate son, Etienne Grandet.
Jeanette MacDonald is credited simply as Marietta, the title character of the story and an assumed name. Her real full name and royal title is Princess Marie de Namours de la Bonfain. Nelson Eddy is credited simply as Warrington. His military rank and full name is Captain Richard Warrington. Walter Kingsford is credited simply as Don Carlos whose full name is Don Carlos de Braganza.
This film received its initial television broadcast in New York City Friday 19 April 1957 on WCBS (Channel 2), followed by Los Angeles Friiday 7 June 1957 on KTTV (Channel 11), by Philadelphia Sunday 5 January 1958 on WFIL (Channel 6) and by San Francisco Sunday 2 March 1958 on KGO (Channel 7).