Fred Astaire's wife died during filming, so between some takes he would retreat to his trailer and cry. That's why, in some scenes, his eyes look red and swollen.
Mitzi Gaynor was the studio's first choice to play Julie, as she was already under contract to Fox, but Fred Astaire personally asked for Leslie Caron.
The "Texas Millionaire" sequence marks the only time Fred Astaire's singing voice was dubbed in one of his films, done purely for comic effect. The vocal was performed by Thurl Ravenscroft, well known as the voice of Tony the Tiger in Frosted Flakes commercials as well as the uncredited vocalist on "You're a Mean One, Mr. Grinch" in Como o Grinch Roubou o Natal! (1966).
Leslie Caron told Fred Astaire that she wanted to create her own costumes for the film. Astaire told her: "OK, but no feathers, please", recalling the utter exasperation he had with an elaborate ostrich feathered dress that Ginger Rogers insisted on wearing in O Picolino (1935), earning Rogers the nickname of "Feathers". Feathers started shedding from Rogers' dress, creating a huge distraction during filming. The shedding feathers nightmare was satirically recreated in a dance in Desfile de Páscoa (1948) with Astaire and Judy Garland.