It was in the last musical sequence of the film that Jerry Mulligan (played by the legend that is Gene Kelly) took on the part of "Chocolat" the muscular, white tighted Toulouse-Lautrec character.
The scene took place in a Montmartre cafe setting with blonde Can Can girls led by Lise Bouvier (played by Lesley Caron - Kelly's love interest in the film and a fine dancer) who I can only assume was playing the role of Jane Avril.
Correct me if i'm wrong, but I hope I'm not.
Look out also for Adam Cook (played by Oscar Levant) the struggling concert pianist who slips into a daydream fantasy and performs on the grand stage. A fantastic pianist who exhibits his skills and who comically takes on the roles of the violin players, conductor and admiring fans in the box.