This sounds too good to be true, but such things happened, I suppose:

Helene Chadwick came from a very wealthy family in upstate New York (the town, Chadwick, was named after them), where her father owned a silk mill and her mother was an opera singer. On a visit to New York she was persuaded by an artist friend to pose for one of his paintings. A film producer saw the work, and after contacting Helene discovered that she was an experienced horsewoman, which is what he needed for a film he was shooting.

Her star dimmed by the late 30s, as they always do. In 1940 she fell down and died of her injuries. No more infirmation seems to be available. She just . . . fell.