Kate O'Mara was an English film, stage and television actress, and writer. O'Mara made her stage debut in a 1963 production of The Merchant of Venice. Her other stage roles included Elvira in Blithe Spirit (1974), Lady Macbeth in Macbeth (1982), Cleopatra in Antony & Cleopatra (1982), Goneril in King Lear (1987), The Rani in Doctor Who and Marlene Dietrich in Lunch with Marlene (2008).

The Rani is a fictional character in the British BBC science fiction television series Doctor Who, portrayed by Kate O'Mara. She is a renegade Time Lord, and a nemesis of the series' title character, a Time Lord known as the Doctor. The Rani is an amoral biochemist who experiments on humans and other species, and considers everything secondary to her research. The character appeared in two classic serials, The Mark of the Rani (1985) and Time and the Rani (1987), before the original run of Doctor Who went off the air in 1989. The Rani later appeared as the principal villain in Dimensions in Time, a 1993 Doctor Who charity television special for BBC Children in Need. The character has since been featured in multiple Doctor Who audio dramas and novels.