Celeste Holm

Best supporting actress, Gentlemen's Agreement (1947)
Her screen test for the anti-Semitism-themed film was so powerful that Elia Kazan used the footage in the film. She won the Oscar the next year, the first of her three nominations.
Says Holm: "I wore a gray taffeta dress I had sewed. Why not? It only took me two days — I knew I wasn't going to win. But [actor] Ronald Colman told me he was sure I would. Then I did! As I was leaving, he said, 'Told ya.' I celebrated with George Cukor and Gloria Swanson."