In her autobiography "Speed Bumps" Teri Garr (in 1965, a young background dancer) reveals she was Ann-Margret's double for many shots in the body painting sequence and that the long and messy shoot involved wallowing in colored pudding for hours.
Ann-Margret rides a 500cc Triumph T100C Tiger motorcycle in the film. Later, she herself featured in Triumph Motorcycles's official advertisements in the USA.
Although production wrapped in late 1965, a campy pop art prologue/epilogue (comic book-style words like "POW!," "WHAM!", etc. superimposed over Ann-Margret as she swung across screen on a swing, echoing Bye Bye Birdie (1963)'s filmic bookends) was subsequently filmed to cash in on the success of TV's Batman (1966), which debuted in early 1966.
Obligatory rear view mirror in Ric Colby's Convertible missing or present depending on scene and camera viewpoint.
The character Kelly Olsson is portrayed by actress Ann Margaret who was born Ann-Margret Olsson.