José Luis de Vilallonga, 9th Marquess of Castellbell

Born in Madrid, Vilallonga – who also went by the surname of Cabeza de Vaca – was a Grandee of Spain and part of the nobility, holding the title of Marquess of Castellbell.

He spent the first two years of his life at a clinic in Munich, to recover from an intestinal condition with which he was born. His grandmother had a powerful influence on his education, which was very broad and advanced for the time. He studied at the Jesuits of Barcelona and in other schools from which he was often expelled for misbehavior.

Upon the declaration in 1931 of Spain's Second Republic his family went into exile in Biarritz, France, but returned six months later. When the Spanish Civil War erupted in 1936, Vilallonga was studying at École Saint-Elme, a Dominican school in Arcachon, but his father ordered him back to Spain to fight on the side of the Nationalists. His father was an enthusiastic supporter of the rebel side, and at age 16 the younger Vilallonga was a serving member of a Nationalist execution platoon,[8] as a provisional second lieutenant of Requetés.

After pursuing a four-year long career in diplomacy, he married his first wife Esyylt Priscilla "Pip" Scott-Ellis, a daughter of Thomas Scott-Ellis, 8th Baron Howard de Walden, while he was working as an attaché in London. They met in January 1944 and they married at Sanlúcar on 20 September 1945. Her family did not approve and none of them could attend the wedding. His father-in-law was so unimpressed by him that he had his will changed in the faint hope of protecting his daughter's inheritance.[9] He then became interested in journalism and literature, his first works being at Diario de Barcelona. After World War II, de Vilallonga became increasingly disenchanted with Francoist Spain, and he left the Spanish diplomatic service to live abroad.

In 1954 his first novel, The Ramblas End in the Sea, was published, causing the Spanish military government censor to issue a ban on his reentry to the country. He then obtained work as a foreign correspondent for the national press agency EFE and for the magazines Paris Match, Marie Claire and Vogue. His social connections and ability to relate gossip among Europe's jet set enabled him to regularly sell magazine articles, in addition to authoring four autobiographical tell-all books about his numerous love affairs.[8] After recording taped interviews with Spain's King Juan Carlos, he wrote the first ever and only authorised biography of king Juan Carlos I, titled El Rey and published in 1993.[10]

He had a brief step through politics, that included toying with the Socialist Party of Spain.

Vilallonga's acting career came through as a result of his good connections with many prominent figures of the artistic world. He made his film debut in the 1958 Louis Malle film The Lovers. Throughout the late 1950s and 1960s, Vilallonga appeared in numerous films in both Europe and Hollywood, working with prominent directors like Federico Fellini, Agnès Varda, Fred Zinnemann and John Schlesinger.

Though he refused a Hollywood acting contract, a highlight in his acting career was a role as "José da Silva Pereira," the dashing Brazilian multimillionaire whom Holly Golightly (played by Audrey Hepburn) planned to marry in Blake Edwards' classic movie, Breakfast at Tiffany's (1961). He also appeared as the debonair Prince Cesare della Romita, who becomes Julie Christie's second husband in Darling (1965).