Born in Edinburgh in 1950, Duncan acted on the stage for a number of years before appearing on British television in guest roles on such shows as “The New Avengers” and “Dick Turpin,” as well as a brief recurring role on “Colin’s Sandwich.” She landed roles in mini-series such as “Dead Head” and “Reilly: Ace of Spies,” and regular series such as “Kit Curran.” She appeared in British television movies such as “Rainy Day Women” in 1984 and “Samson & Delilah” in 1985. She also had a part on the acclaimed British mini-series “Traffik,” in 1988. Film credits in the United States include “City Hall” in 1996, and “An Ideal Husband,” and “Mansfield Park” in 1999. She also provided the voice for a droid in “Star Wars: Episode One 1- The Phantom Menace” that year. In 2004, she appeared in the romantic comedy “Under the Tuscan Sun.”
But it has been on the stage that Duncan has done her most critically acclaimed work. In 2002, she won the Tony Award for best actress for her performance on Broadway in “Private Lives.” And she was nominated for a Tony Award in 1988 for her performance in “Les Liasions Dangereuses.” Duncan also won the 2001 London Critics Circle Theater Award for Best Actress for her performance in “Mouth to Mouth” at the Royal Court Downstairs Theater. And she was awarded the 1988 London Evening Standard award for Best Actress for a production of “Cat On a Hot Tin Roof.” In addition to “Rome,” she also starred in the Agatha Christie television adaptation of “Poirot: The Mystery of the Blue Train,” in 2005.