Dame Siân Phillips (born Jane Elizabeth Ailwen Phillips on 14 May 1933) is a Welsh actress born in Gwaun-Cae-Gurwen, Glamorgan. She grew up speaking only Welsh for much of her childhood, learning English partly by listening to the radio, and was educated at Pontardawe Grammar School, where her Welsh teacher gave her the name Siân. She went on to read English and Philosophy at University College Cardiff, part of the University of Wales, graduating in 1955.
That same year she won a scholarship to the Royal Academy of Dramatic Art in London, training alongside Diana Rigg and Glenda Jackson and winning the Bancroft Gold Medal for her performance in Hedda Gabler. Her acting career had, in fact, begun far earlier: she made her professional debut with BBC Radio in Wales at the age of eleven and won her first drama award at the National Eisteddfod in Llandybie in 1944.
Phillips became one of Britain's most celebrated actresses of stage and screen, winning a BAFTA and a Royal Television Society award for her performance as the scheming Livia in the BBC's I, Claudius (1976). She later played the Reverend Mother Gaius Helen Mohiam in David Lynch's Dune (1984), and toured widely in the one-woman stage show Marlene, playing Marlene Dietrich, for which she received Tony and Olivier Award nominations.
She was appointed CBE in 2000 and made a Dame Commander of the Order of the British Empire in 2016 for services to drama. Phillips was married first to Donald Roy, who went on to found the Drama Department at the University of Hull, and later to the actor Peter O'Toole.