She began acting in her adolescence with the Coventry Repertory Company after studying at the Froebel Institute, and was a film extra in 1935 before appearing in The Crimson Circle the following year. Her next film was The Cardinal, and she had a small role in The Spy in Black, but it was her fourth film, the epic London Films adaptation of A. E. W. Mason's The Four Feathers, that made her a film star, acting opposite John Clements, Ralph Richardson, and C. Aubrey Smith. Her peak of success came with the fantasy film The Thief of Bagdad, which she also made for Alexander Korda's London Films. Korda took charge of her career after this point and brought her to Hollywood where he set her asking price at $50,000 per film. However, as Duprez had not yet achieved the level of popularity in the United States that she had in the United Kingdom, this tactic only served to place her out of contention for most roles. When she was finally released from Korda's contract, she appeared in such low budget fare as They Raid by Night, Little Tokyo, U.S.A., and Tiger Fangs. Clifford Odets' grim None But the Lonely Heart, in which she co-starred with Cary Grant and Ethel Barrymore, commenced a brief return to films of higher production values. Duprez joined a top ensemble cast in René Clair's film version of Agatha Christie's And Then There Were None. That same year, she appeared opposite John Loder in The Brighton Strangler. In the film noirCalcutta, she starred with Alan Ladd, Gail Russell, and William Bendix. After a few more motion pictures, Duprez moved to New York City for a brief career on and off Broadway. She appeared in "The Last Tycoon," an episode of the Robert Montgomery Presentstelevision show in 1951, and her final credited film performance was in One Plus One, also titled Exploring the Kinsey Reports.
Music
Duprez composed "I Woke Up and Started Dreaming", a song that Bing Crosby's music company bought and published.
Radio
On 10 September 1944, Duprez starred in "Forever Walking Free," an episode of Silver Theater on CBS radio. She also starred in the June 20, 1946 episode of Suspense, titled "Your Devoted Wife," also on CBS radio.
During World War II, after her father's death, Duprez and her mother were unable to use money that they had in England. They sold or pawned jewels to stay afloat financially, and eventually Duprez sent her mother to Australia, where she had access to the British funds. Duprez married her first husband Frederick Beauchamp, a wealthy Harley Street doctor, in 1935, but they divorced in 1942 when his jealousy of her film stardom had eroded their marriage. She married for a second time in October 1948 to George Moffett, Jr., a wealthy sportsman. They had two daughters, but divorced in 1965. Duprez lived in Rome, Italy, for several years, then returned to London to live out the remainder of her life in a flat in the affluent Knightsbridge area, having a close relationship with an English nobleman. She died there, after a long period of illness on 30 October 1984 at age 66 and was buried at Streatham Park Cemetery.
