David McCallum (September 19, 1933 - September 25, 2023) was a Scottish actor and musician. He gained wide recognition in the 1960s for playing secret agent Illya Kuryakin in the television series The Man from U.N.C.L.E. His other notable television roles include Carter in Colditz (1972–1974) and Steel in Sapphire & Steel (1979–1982). Beginning in 2003, McCallum gained renewed international popularity for his role as NCIS medical examiner Dr. Donald "Ducky" Mallard in the American television series NCIS. On film, McCallum notably appeared 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 pursue a 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 act in films and television shows, but he never achieved the same level of success.

In 2003, he was cast as Dr. Donald "Ducky" Mallard in NCIS. The show was a critical and commercial success, and McCallum became one of the most popular members of the cast. He remained with the show for a 20-year run, and became the longest-serving cast member.

In addition to his acting career, he was also a musician. He has released several albums of folk and pop music, and he also toured extensively.