When Good Neighbor Sam was released in 1964 Jack Lemmon was being taken seriously as a dramatic actor as well as a light comic actor as witnessed by the rave reviews he got for The Apartment and Days of Wine and Roses. While Good Neighbor Sam doesn't stack up against those two films in Lemmon's career, it's still an amusing and pleasing romp.
Have you ever noticed how many films like Good Neighbor Sam start out with a mistaken impression? Through a lie told by Romy Schneider who is the good neighbor that Sam has, people in her life and in his get the impression that they are married. He's married to Dorothy Provine and she's married to Michael Connors. And both for their own reasons have to keep the deception up. All the situations the principal players get into stem from the original white lie.
It would be so much easier if everyone told the truth from the gitgo, but then we wouldn't have a movie.
Lots of familiar names pop up here in support. Edward Andrews as the unctuous boss of the advertising agency Lemmon works for, Louis Nye as the creative private detective who gets it wrong, and last but not definitely not least Edward G. Robinson as the puritanical dairy king.
Minor league Lemmon, but still fun. And as another reviewer says, that theme is unforgettable. You'll have it in your brain for days.