She died from a heart attack at her home in Madrid on 3 January (13), according to the New York Daily News.
Born in South Carolina, she moved to Spain when she was 18 to study philosophy, but got swept up in the culture and never returned to America.
She then launched a career in modelling, appearing in several television adverts before landing her big acting break in 1966's La Ciudad No Es Para Mi (The City Is Not For Me).
Shepard went on to star in A Date in Navarra, where she met her future husband Maunel de Blas, while her other film credits include El Monte de las Brujas (The Witches' Mountain) and El Karate, el Colt y el Impostor (The Stranger and the Gunfighter).
Her younger sister, Judith Chapman, is also a notable actress from hit U.S. TV shows The Young And The Restless and Murder, She Wrote.