Cole and Linda's Hollywood home was also the Martin residence from Bicentennial Man (1999).
'Kevin Kline (I)' played the piano himself in the scenes where his character plays.
The old Cole Porter make-up took 5 hours to complete.
A lot of singing in the movie, especially that done by Kline, was recorded on set.
Ashley Judd was almost never cast because the producers and director thought that she was beyond their budget. Her agent later contacted and informed them that Judd was interested in playing Linda.
Many scenes in the film are actually one continuous shot. The scene where Cole is visiting the gentleman's club during the song "Love For Sale" is a good example. The scene is supposed to be representing three different times where Cole was in the club. Most of the dancers are costume personnel who would perform costume changes on other actors and themselves and then walk back into the shot. Even the singer changes hair pieces and earrings in this shot.
Real Linda Porter was from 8 to 14 years older (depending on what biography you read) than Cole, but Ashley Judd is 21 years younger than Kevin Kline.