Marlon Brando and Frank Sinatra HATED each other while doing this film and in the years following it.Brando asked Sinatra for some singing lessons,but Sinatra (who was already upset over the fact that he was cast as Nathan Detroit,when he wanted the part of Skye Masterson)wanted to be the star singer in the production and didn't want any one to be better than he was.He told Brando to get lost,so to get back at him Marlon kept screwing up the scene in the diner where Sinatra was eating cheesecake so that he would have to keep eating,eating and eating.In the later years,Sinatra gave Brando the nickname "Mumbles" or "Mr.Mumbles" because of the way he talks.