Nancy "Slim" Keith, Lady Keith (July 15, 1917 – April 6, 1990) was a New York socialite and fashion icon during the 1950s and 1960s, exemplifying the American jet set. She is perhaps best known, along with her friend Babe Paley, as the thinly veiled inspiration for characters in Truman Capote's novel Answered Prayers.
Born Mary Raye Gross in Salinas, California (her mother changed her name to Nancy), by age 22, she had appeared on the cover of Harper's Bazaar. She graced the Best Dressed list almost annually, and in 1946 won a Neiman Marcus Fashion Award (as Mrs. Leland Hayward). She was also dubbed the original "California Girl", for her golden looks and athletic ability. She considered a career in opera, before deciding it was too demanding.
When she was 16, Slim left school and moved to Death Valley where she met William Powell. Through Powell, she met William Randolph Hearst and his mistress Marion Davies. She thus became a Hollywood socialite, and was frequently seen at parties with Gary Cooper and Cary Grant. She was pursued by Clark Gable, as well as Ernest Hemingway.