CNN and others reported her death, citing niece Amy Phillips.

Though much honored by Hollywood (she was nominated for Oscars during three of the four years she was primarily active), Ms. Holm was more a featured player than a headlining star. But her performances were so reliably expert and witty, she often eclipsed the actors she was hired to support. And she was lucky in her choices. She won an Academy Award as Best Supporting Actress for her performance as a smart fashion editor in Elia Kazan's 1947 dramatic examination of anti-Semitism, "Gentleman's Agreement." It was only her third film. She was Frank Sinatra's cynical equal as a photographer in "High Society" (1956), the all-star movie musical of The Philadelphia Story. She starred again with Sinatra in the comedy "The Tender Trap" (1955), playing a philosophically suffering maiden-in-waiting to his womanizing press agent.

In her most famous film, Ms. Holm played the common-sensical, yet savvy best friend to Bette Davis' tempestuous stage diva in "All About Eve," Joseph L. Mankiewicz acid love letter to the theatre. She was also one of the backstage drama's off-screen narrators. Mankiewicz was fond of Ms. Holm's mellifluous voice, which effortlessly expressed all sorts of knowing sophistication. He also used it in "A Letter to Three Wives" as the voice of the unseen friend who has stolen away one of the trio's husbands. She was nominated for Oscars for both "Come to the Stable," in which she played a nun, and "All About Eve."