Who was known for a role in an Agatha Christie movie and acted in Theater of Blood?
Theatre of Blood: Theatre of Blood (also known in the United States as Theater of Blood) is a 1973 horror film starring Vincent Price as vengeful actor Edward Lionheart and Diana Rigg as his daughter Edwina. Theatre of Blood:  The cast includes distinguished actors Harry Andrews, Coral Browne, Robert Coote, Jack Hawkins, Ian Hendry, Michael Hordern, Arthur Lowe, Joan Hickson, Robert Morley, Milo O'Shea, Diana Dors and Dennis Price. Joan Hickson: Joan Bogle Hickson, OBE (5 August 1906 – 17 October 1998) was an English actress of theatre, film and television. Joan Hickson:  She was particularly known for her role as Agatha Christie's Miss Marple in the television series "Miss Marple".
Joan Hickson