I think the 1941 Waterloo Bridge is a lovely movie of its kind and Leigh is lovely and terrific in it. Obviously not a ballet dancer but she has a neck befitting any Swan Queen. She wanted Olivier to play Roy and got Robert Taylor instead so we can only dream of what might have been, sigh.
There's an earlier version of the story with Mae Clarke (best known today for getting a grapefruit in the face, courtesy of James Cagney). I think there have been a total of 3. It's pre-Code and directed by James Whale, but not as interesting as you might think, although Clarke is excellent. Comparing and contrasting the plot line in both pictures is an interesting exercise.