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 (1936), and she had a small role in The Spy in Black (1939), but it was her fourth film, the epic London Films adaptation of A. E. W. Mason's The Four Feathers (1939), 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 (1940), which she also made for Alexander Korda's London Films (on locations in the United Kingdom, northern Africa, and the Grand Canyon in Arizona).
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.
