David McCallum (September 19, 1933 — September 25, 2023) was a Scottish actor and musician. He gained wide recognition in the 1960s for his role as secret agent Illya Kuryakin in the television series "The Man from U.N.C.L.E." Among his other notable television roles were Carter in "Colditz" (1972–1974) and Steel in "Sapphire & Steel" (1979–1982). Beginning in 2003, McCallum regained international popularity thanks to his role as NCIS medical examiner Dr. Donald "Ducky" Mallard in the American television series "NCIS." In film, McCallum had a notable appearance in "The Great Escape" (1963).

He was born in Glasgow, Scotland, to David McCallum Sr., an orchestral violinist, and Dorothy (née Dorman), a cellist. He began his acting career in the early 1950s, appearing in British television shows and films. In 1957 he moved to Hollywood to continue his career in American cinema.

His breakthrough role came in 1964, when he was cast as Illya Kuryakin in "The Man from U.N.C.L.E." The show was a huge success, and he became an international star. After the show ended in 1968, he continued to appear in films and television shows, but never again reached the same level of success.

In 2003 he was cast as Dr. Donald "Ducky" Mallard in "NCIS." The show received critical acclaim and commercial success, and McCallum became one of the most popular members of the cast. He remained on the show for 20 years and became its longest-running cast member.