Debut role of future adult film star Marilyn Chambers portraying Barney's Girl. She was billed in the credits as Evelyn Lang. She was 18 and still in high school. Her dream was to make it big in mainstream films, but two years later she was talked into starting in the X-rated movie Behind the Green Door. After that, no one would hire her for mainstream films for many years.
George Segal was not the initial choice to star opposite Barbra Streisand; she wanted her fellow First Artists producer Sidney Poitier, who was rejected when it was felt that audiences might not yet be altogether accepting of an interracial relationship in a major comedy release.
Star Barbra Streisand between takes painted and studied painting. The actress had to wear special plastic gloves in order to protect her make-up manicure for her film character. Reportedly, because Streisand was a fan of the modernist artist Frank Stella, producer Ray Stark gave her an artist's smock embroidered with the name "Streisella".
The interracial relationship in the Bill Manhoff source stage play was reflected in the original Broadway production where the couple were portrayed by Alan Alda and African-American actress Diana Sands. If Sidney Poitier had been cast in the lead male role opposite Barbra Streisand, as was considered, then the picture would have preserved the inter-racial relationship of the play, but with the racial types gender reversed.
Ken Adam: Uncredited, the film's design supervisor and famed James Bond franchise production designer as a middle-aged man.