The acting career of Gayle Hunnicutt, who has died aged 80, could be defined in two acts. As an up-and-coming starlet in Hollywood she was often cast for her stunning beauty. Then, after marrying the British actor David Hemmings, she moved to the UK, where she played big parts in two major television series, The Golden Bowl (1972) and Fall of Eagles (1974).

After a divorce she married the journalist and editor Simon Jenkins, and alongside her acting career became a fixture of the British social scene. She may, though, be best remembered for the final three seasons of Dallas, from 1989 to 1991, in which she played Vanessa Beaumont, an English aristocrat whose long-ago affair with JR Ewing produced a son he had never known existed.

Hunnicutt was born in Texas, not far from Dallas in Fort Worth. Her father, Sam, was a colonel in the army; her mother, Mary (nee Dickerson), gave birth to Gayle while her husband was serving in New Caledonia during the second world war. Her parents did not support her desire to go to college, but she won a scholarship to the University of California, Los Angeles, and paid for her time there with part-time work while studying English and theatre.

Spotted in a college production by a talent scout from Warner Brothers, she made her debut on the television naval comedy Mister Roberts at the age of 23 in 1966, and then in Roger Corman’s Peter Fonda/Nancy Sinatra film Wild Angels, about a San Pedro motorcycle gang.

Once asked whom she would most want to look like, Hunnicutt replied Audrey Hepburn, whose beauty, like hers, was often described as “porcelain” or even “cold”. But Hepburn also projected a certain vulnerability, whereas Hunnicutt seemed to carry her beauty naturally. Rather than Hollywood’s typecasting of her as a beauty queen, she needed parts that played on a contrast between fragile beauty and steely character.

She caught notice in 1967 for her role as a woman trying to con Jed Clampett out of his fortune in a two-part episode of The Beverly Hillbillies on TV, and then playing opposite James Garner in the film Marlowe (1969) as the older sister, Mavis Wald, protecting secrets in a film based on Raymond Chandler’s novel The Little Sister.

By then she had met Hemmings, at a party at the actor Peter Lawford’s beach house. She described it as love at first sight, and they married in 1968. Hemmings, already a major star after Blow Up, characterised them as the “poor man’s Elizabeth Taylor and Richard Burton”, and although Hunnicutt “always thought that was silly”, her new husband seemed intent on replicating the conflict of the Taylor/Burton relationship. Within three months of the wedding he began a very public affair with the actor Samantha Eggar, yet despite his serial infidelity they remained married, and moved to Britain, where their son, Nolan, was born.

She co-starred with Hemmings in Fragment of Fear (1970) , and then was directed by him in Running Scared (1972) with Robert Powell. In 1973 she played in Scorpio, in which Michael Winner wasted the talents of Burt Lancaster and Alain Delon, then again alongside Hemmings in Voices, which was less interesting than her next horror film, The Legend of Hell House.

Being in Britain brought her theatre opportunities, and in 1973 she was in her fellow American Michael Rudman’s Hampstead theatre production of Peter Handke’s Ride Across Lake Constance, alongside Alan Howard, Jenny Agutter, Nigel Hawthorne and Nicola Pagett.

In 1972 she also starred on the small screen in the BBC’s adaptation of Henry James’s The Golden Bowl as Charlotte Stant, playing, for the first time, a transatlantic character. She followed up with another success on the BBC as the Tsarina Alexandra in Fall of Eagles (1974), and that year also played in Nuits Rouges (aka Shadowman in its English dubbed version), George Franju’s homage to the fictional criminal genius Fantômas, in which she was memorable in an Irma Vep-style bodysuit being chased by police across the Paris rooftops.

She revisited Fantômas in three episodes of the eponymous 1980 French mini-series, directed by Claude Chabrol and Luis Buñuel’s son Juan Luis. In the BBC’s 1978 TV film Dylan she played Liz Reitel, a woman having an affair with Ronald Lacey’s Dylan Thomas, drinking his way through his ill-fated final American tour.

Hunnicutt had divorced Hemmings in 1974, and married Jenkins in 1978, by which time she was a notable presence on stage and in quality television roles. In London in 1979 she ranged from playing Hedda in the Watermill theatre’s production of Ibsen’s Hedda Gabler to being Peter Pan at the Shaftesbury theatre. That year she also starred in a double episode of The Return of the Saint with Ian Ogilvy, which was later repackaged as a TV movie.

She would play in another Saint TV movie, The Brazilian Connection (1989) with Simon Dutton as Simon Templar. She also returned to Raymond Chandler as a femme fatale opposite Powers Boothe in an episode of the mini-series Marlowe, Private Eye in 1983. In the first episode of The Adventures of Sherlock Holmes (1984) opposite Jeremy Brett, she played Holmes’ great female rival, Irene Adler. In 1985 she starred as Donna Lloyd with Gene Hackman and Matt Dillon in Arthur Penn’s thriller film, Target.

Her most personal project was a two-hander, The Life and Loves of Edith Wharton, which debuted in 1995 at the Hampstead theatre and toured for many years afterwards; according to Jenkins, she identified with the troubled Anglo-American writer. Later she played the writer Mary Wollstonecraft in another two-hander, The Two Marys. Her last screen role came in a 1999 episode of CI5: The New Professionals.

Having written a book called Health and Beauty in Motherhood in 1984, two decades later she published Dearest Virginia, a moving collection of her father’s love letters written while he was serving in the South Pacific.

She and Jenkins divorced in 2009; her sale of the Primrose Hill house they had lived in for three decades became an episode of a 2012 reality show, Selling London.

She is survived by Nolan, another son, Edward, from her marriage to Jenkins, and five grandchildren, Poppy, Theo, Oscar, Dash and Nia.

• Gayle Hunnicutt, actor, born 6 February 1943; died 31 August 2023