""Folies Bergeres" for Liliane Montevecchi in the original production of Nine.
Interestingly, in early drafts of the script, Montevecchi's part of producer Liliane La Fleur was written to be played as a flamboyant queen in obvious drag. I'm not sure how long that idea stayed; it may have lasted up until the point director Tommy Tune decided to eliminate all the male characters from the show except for Guido. I saw an excellent student production at NYU 15 or 20 years ago where the director had received special permission to make changes based on original work notes and early scripts and Liliane was indeed played by a man. It worked fine."
In the Samuel French edition of the script I have from some years back there are notes about which characters could be played by men and the adjustments (mostly switching around of pronouns, and of course the characters' names) to the dialogue if that option is chosen.
The story that I had heard was that La Fleur was set to be cast as a man but they were having trouble finding a suitable actor so they started seeing women. Liliane Montevecchi floored them with her audition and the role was hers.