Joan Fontaine in 1978 Photo: IC

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

The Hollywood Reporter magazine said Fontaine's death from natural causes was confirmed by her assistant.

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

The honor gave Fontaine the distinction of being the only actor or actress to win an Academy Award for a starring role in one of Hitchcock's many films.

De Havilland, who was nominated that year for Hold Back the Dawn, went on to win two Oscars of her own. Now aged 97, De Havilland resides in Paris.

Her victories established the feuding sisters as the only two siblings ever to both win Academy Awards for acting.

Fontaine also earned Oscar nominations for her star turns in Hitchcock's 1940 American debut, Rebecca, as a young bride haunted by the memory of her husband's deceased first wife; and the 1943 romantic drama The Constant Nymph, falling for a dashing composer.

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