Fiona Frances Elaine Campbell-Walter, formerly Baroness Thyssen-Bornemisza de Kászon et Impérfalva, (born 25 June 1932) is a New Zealand-born British model.
Campbell-Walter was known for her relationship with Greek shipping heir Alexander Onassis, whom she began an affair with after separating from her husband, Baron Hans Heinrich Thyssen-Bornemisza de Kászon et Impérfalva.
Her mother was the eldest daughter of Sir Edward Campbell, 1st Baronet, and was a granddaughter of Arthur John Warren.
She was also photographed by John French, Elsbeth Juda, Norman Parkinson, and David Bailey and modelled for Christian Dior, Jacques Fath, and Elsa Schiaparelli.
[1] On 17 September 1956 she married Baron Hans Heinrich Thyssen-Bornemisza de Kászon et Impérfalva at Castagnola, a Swiss village on the coast of Lake Lugano.