Chambers was born on 11 March 1964, in Doncaster, the daughter of John Chambers, a consultant obstetrician and gynaecologist, and his wife Noelle, née Strange. She attended St. Mary's School and her secondary education was at St Swithun's School, Winchester, Hampshire. She then trained at the Webber Douglas Academy of Dramatic Art in the 1980s, where she was a classmate of actor Ross Kemp.