Alexandra Knatchbull is the daughter of Norton Knatchbull, 8th Baron Brabourne and his wife, Penelope Meredith (née Eastwood), known at the time of her birth as Lord and Lady Romsey. She is a great-great-great-great-granddaughter of Queen Victoria and a third cousin twice removed of the Queen. Through Prince Philip, Duke of Edinburgh, she is the third cousin of Prince William, Duke of Cambridge. She is in the line of succession to the British throne.
Alexandra Victoria Edwina Diana Knatchbull was born on 5 December 1982 at King’s College Hospital, London, and christened at Romsey Abbey on 12 March 1983. She was one of 17 godchildren of Diana, Princess of Wales.
She studied theology at Regent’s Park College, Oxford and obtained an upper-second class degree in 2005. She served a year in office as Captain of Boats. In the autumn of 2006, she began graduate studies at the Edmund A. Walsh School of Foreign Service, Georgetown University focusing on International Security.