Jillian Noel Hennessy is a Canadian actress and singer. She is most known for her roles on the American television series Law & Order, on which she played prosecutor Claire Kincaid for three seasons, and Crossing Jordan, on which she played the lead character, Jordan Cavanaugh, for six seasons. She has also acted in films such as RoboCop 3 and Most Wanted, and the independent films Chutney Popcorn and The Acting Class, the latter of which she also wrote and co-directed.

Dead Ringers is a 1988 psychological thriller film starring Jeremy Irons in a dual role as identical twin gynecologists. David Cronenberg directed and co-wrote the screenplay with Norman Snider. Their script was based on the lives of Stewart and Cyril Marcus and on the novel Twins by Bari Wood and Jack Geasland, a "highly fictionalized" version of the Marcuses' story.