Desmond Wilkinson Llewelyn was born on 12 September 1914 at Blaen-y-Pant House in the Bettws area of Newport, Monmouthshire, the son of a coal mining engineer. He was educated at Radley College, where he became involved in theatrical productions, having originally intended to train for the ministry.
During the Second World War, Llewelyn served as a lieutenant with the Royal Welch Fusiliers and was taken prisoner by German forces during the retreat to Dunkirk in 1940, spending the remainder of the war as a prisoner of war. After his release he resumed his acting career on stage and in British films and television.
Llewelyn became internationally famous for playing Q, the gadget-master of the British Secret Service, appearing in seventeen James Bond films between From Russia with Love (1963) and The World Is Not Enough (1999). He appeared opposite all five actors to play Bond during his lifetime - Sean Connery, George Lazenby, Roger Moore, Timothy Dalton and Pierce Brosnan - missing only Dr. No (1962) and Live and Let Die (1973).
Llewelyn was killed in a car accident on the A27 near Berwick, East Sussex, on 19 December 1999, shortly after returning from a Bond-related book signing event; he was 85. A biography, Q: The Biography of Desmond Llewelyn by Sandy Hernu, was published the same year.