Joan Mary Waller Greenwood was an English actress. Her husky voice, coupled with her slow, precise elocution, was her trademark. She played Sibella in the 1949 film Kind Hearts and Coronets, and also appeared in The Man in the White Suit (1951), Young Wives' Tale (1951), The Importance of Being Earnest (1952), Stage Struck (1958), Tom Jones (1963) and Little Dorrit (1987).

Kind Hearts and Coronets is a 1949 British crime black comedy film directed by Robert Hamer. It features Dennis Price, Joan Greenwood, Valerie Hobson and Alec Guinness; Guinness plays eight characters. The plot is loosely based on the novel Israel Rank: The Autobiography of a Criminal (1907) by Roy Horniman. It concerns Louis D'Ascoyne Mazzini, the son of a woman disowned by her aristocratic family for marrying out of her social class. After her death, a vengeful Louis decides to take the family's dukedom by murdering the eight people ahead of him in the line of succession to the title.