Trivia

Actor Alan Arkin grew a black mustache and shaved the mid section of the top of his head for his lead role of Barney Cashman in this movie.

Alan Arkin's character is 45 in the film. At the time of filming, Arkin was 38.

The film was made and released about three years after its source stage play of the same name by Neil Simon was first performed in 1969. The original Broadway production of "Last of the Red Hot Lovers" opened at the Eugene O'Neill Theater on 28th December 1969 and ran for 706 performances until 4th September 1971. The play was nominated for four Tony Awards in 1970 including Best Play, Best Direction (Robert Moore) , Best Actor (James Coco) and Best Actress (Linda Lavin) but failed to win any category. The play's setting is described in its intro as being "An apartment in the East Thirties. December, August and September - late afternoon".

In September 1972, Paramount widely distributing movie on a double bill with Woody Allen's Tombe les filles et tais-toi (1972).

Actors Alan Arkin and Paula Prentiss previously appeared together in Catch-22 (1970).