Mrs. Guinness was born in Hampstead, London, United Kingdom, on November 9, 1967. She is an heir by direct descent of the 18th century Irish brewer Arthur Guinness. Her paternal grandmother was Diana Mitford, one of the legendary Mitford sisters. She is the daughter of brewery heir Jonathan Guinness and renowned French beauty Suzanne Lisney. As a child, she grew up in the country houses owned by her family in England and Ireland. She spent her holidays in an 18th-century former monastery in Cadaqués, Catalonia, where the neighbors included Salvador Dalí, Man Ray, Marcel Duchamp, Dieter Roth, and Richard Hamilton.