Jean Simmons, a radiant British actress who as a teenager appeared opposite Laurence Olivier in "Hamlet" and emerged a star whose career flourished in the 1950s and 1960s in such films as "Guys and Dolls, "Elmer Gantry" and "Spartacus," has died. She was 80. Simmons, who won an Emmy Award for her role in the 1980s miniseries "The Thorn Birds," died Friday evening at her home in Santa Monica, said Judy Page, her agent. She had lung cancer.