Smooth, refined British star Leo Genn is known for his relaxed charm and "black velvet" voice. Before becoming an actor, he received a law degree at Cambridge and worked as a barrister in the early '20s. In 1930 he debuted onstage; for several years he continued earning money with legal services, meanwhile gaining experience in both plays and films. In 1939 he finally gave up the law to make his Broadway debut. He served with the Royal Artillery during World War II; in 1943 he was promoted to lieutenant colonel, and in 1945 he was awarded the Croix de Guerre. On several occasions during the war he was granted leave to appear in films. At war's end he became one of Britain's investigators of war crimes at the Belsen concentration camp and went on to be an assistant prosecutor for the Belsen trial. After his small but noteworthy role as the Constable of France in Laurence Olivier's film Henry V (1944), he was invited to the U.S., where he had a great theatrical triumph in the 1946 Broadway production of Lillian Hellman's Another Part of the Forest. His stage and screen career flourished afterwards in both the U.S. and England. Onscreen he was usually cast in smart, likable, subtle character leads and supporting roles. For his portrayal of Gaius Petronius, Nero's counselor, in Quo Vadis (1951), he received a "Best Supporting Actor" Oscar nomination.