This was the only film in which Clark Gable performed a dance number. He spent 6 weeks rehearsing the steps with the dance director, George King, and practicing at home with his wife, Carole Lombard. Because of his fear of messing it up during a take, the set was closed during the filming of this sequence.
When Clark Gable performed "Puttin' on the Ritz", the choreography called for him to be carried offstage by the women of Les Blondes. That scene was filmed last, in case he was injured while being carried. On the day it was shot, Carole Lombard came to watch and was amazed that they got it in just one take.
The screen between the bar and the hotel lobby is an optical illusion that alternates between a cross and a swastika.
Joan Crawford desperately wanted the role of Irene, but Norma Shearer's late husband, producer Irving Thalberg, had left her his MGM stock, and she had first choice of parts.