Oscar-winning actress Joan Fontaine, whose film career was marked by a long-running rivalry with her sister, Olivia de Havilland, died on Sunday at age 96 at her home in Carmel, California, Hollywood's two trade publications reported.

The Hollywood Reporter said Fontaine's death from natural causes was confirmed by the star's assistant, Susan Pfeiffer.

Among Fontaine's most memorable films was the Alfred Hitchcock picture Suspicion, co-starring Cary Grant, for which she won an Academy Award in 1942, beating out her older sister in the competition.

Joan Fontaine, left, appears in the famous biblical story 'The Story of Judith' on CBS-TV's General Electric Theater in a 1960 file photo with actress Argentina Brunetti. (Associated Press)

The honour gave Fontaine the distinction of being the only performer, actor or actress, ever to win an Academy Award for a starring role in one of Hitchcock's many movies.

De Havilland, who was nominated that year for Hold Back the Dawn, went on to win two Oscars of her own for leading roles in the 1946 film To Each His Own and the 1949 picture The Heiress.

Fontaine also earned Oscar nominations for her star turns in Hitchcock's 1940 thriller Rebecca, co-starring Laurence Olivier, and the 1943 romantic drama "The Constant Nymph, opposite Charles Boyer.

Fontaine appeared mousy and innocent in her early movies but later carefully selected her roles and went on to play worldly, sophisticated women.