I am a HUGE Jack Lemmon fan and this has to be in my humble opinion, for what it's worth, one of Jack's funniest movies. I originally saw it on TV while growing up during the 60's. If memory serves me correctly, I believe Lemmon regretted making this movie and considered it one of his worst. That said... I happen to think it is hilarious, filled with a great cast and memorable scenes of the old Hertz commercials showing bloopers of the ads being filmed of the Hertz man being lowered through the air into a moving car, continually tripping over something whether it be the seat, windshield, or whatever as he is lowered into the car.
Jack Lemmon plays Sam Bissell who is married to Min (Dorothy Provine). He is an employee who works at the bottom entry level of a major Advertising Agency when suddenly he is chosen as an unknown and fresh candidate to be the Account Executive by the head of the Agency's powerful client, "Nurdlinger Dairy" to be their model of what they stand for: wholesome and family-oriented.
Min's beautiful European friend Janet (Romy Schneider) suddenly shows up on Sam & Min's doorstep after separating - and I think, technically divorced - from her husband (played by Mike Connors - formerly "Mannix"). Janet moves into the house next door then learns that her grandfather has died and left her an inheritance of $15 million IF she meets the qualifications of being happily married. Enter Janet's relatives who want in on the inheritance and contest the Will unexpectedly show up at Janet's. The $15 million proves too irresistible to Janet so during the introduction between her relatives, Sam & Min she impulsively introduces Sam as her husband.
To convince Sam (& hesitant Min) to agree to let Sam play her husband until the legal hearing, she offers to share a portion of her inheritance to them. Min hesitantly goes along with the plan. But things get really complex when Janet is falsely introduced to the owner of Nurdlinger Dairy as Sam's wife. The pressure is on when Janet's suspicious relatives hire Louie Nye as a private investigator to find out if Sam is truly exactly who Janet claims him to be--her husband.
Louie the P.I. camps out across the street in a truck disguised as a vacuum-related business. On the truck a vacuum is mounted on top with the vacuum serving as a periscope vessel to enable Louie to spy on them day and night.
It gets even more complicated when Janet's tentatively-divorced husband returns to reconcile but by now, pictures have been unknowingly taken of Sam & Janet for the Nurdlinger Dairy advertisement billboards which are now displayed all over town. And the race is on.
This is a funny movie and will guarantee a lot of laughs.