Julie Andrews' performance of "Le Jazz Hot," along with the verisimilitude of her performance generally, was made possible by her four octave vocal range, which allowed her to sing the low notes of a male tenor to the high notes of a female soprano with smooth transitions.
Before the "Crazy World" number, Victoria Grant (Julie Andrews) does a deal with King Marchand (James Garner): they promise to not keep secrets or hold grudges, they won't plan past tomorrow, and they'll take things one day at a time. According to Andrews, these were the promises she and Blake Edwards made to each other when they married in 1969. They stayed together until Edwards' death in 2010, and both attributed their long marriage to these promises.
This movie had been planned as early as 1978, with Dame Julie Andrews to star alongside Peter Sellers, but Sellers died in 1980, while Andrews and Blake Edwards were filming S.O.B. (1981). Robert Preston was subsequently cast in the role of Carole "Toddy" Todd.
The young man who says Victor is "divine" at rehearsal is Blake Edwards' son and Dame Julie Andrews' stepson, Geoffrey Edwards.
Lesley Ann Warren says that in the scene where Julie Andrews was about to remove her clothes to show Norma she wasn't a man, Warren improvised the line, "Lock the door."