Duncan made her Star Wars appearance in The Phantom Menace as the voice of the droid TC-14, the droid that greets Qui-Gon Jinn and Obi-Wan on the Trade Federation's ship at the start of the film (the man inside the costume was John Fensom). Many years later, she added Doctor Who to her CV by playing the leader of the Mars mission, Adelaide Brooke, in the 2009 special The Waters of Mars. Her role opposite David Tennant's Tenth Doctor is still well remembered - shockingly, her character committed suicide to stop "the Time Lord victorious" from changing established history.