Even though Vincente Minnelli is credited as the sole director, he was sometimes tied up with his divorce from Judy Garland and other directing projects, leaving Gene Kelly to take over the directing duties much to the dismay of the cast and crew.
Oscar Levant, more of a pianist than an actor, signed onto the film because he was a friend of George Gershwin. According to Levant, the cast and crew disliked Gene Kelly due to his condescending attitude and snide remarks.
Leslie Caron had suffered from malnutrition during World War II and was not used to the rigorous schedule of filming a movie. Because she would tire so easily, she was only able to work every other day to the annoyance of Gene Kelly.
Leslie Caron didn't speak English when she landed her first major role. She had a vague understanding of the language due to having an American mother, but was not conversant. Luckily for her, the part didn't have many lines and was comprised of mostly dancing, a skill that Caron was very fluent in.