The Live-Action Cinderella Film You Never Saw
Before it was animated, the 1950 feature Cinderella was performed and recorded in full by costumed actors and models.
That may sound extravagant, but it was actually a cost-saving measure. Walt Disney Productions was about $3 million in the hole when they began storyboarding, and Disney couldn't afford to be as fun and fancy free as he was with 1947's Fun and Fancy Free. Giving animators frame-by-frame reference images actually streamlined the process and cut production costs substantially.
Some of this filmed performance has survived. Compare these live-action production stills to the final animated scene: