David McCallum died of natural causes surrounded by his family       

David McCallum, 'NCIS' star, dies at 90

David McCallum, a Scottish actor best known for playing Donald "Ducky" Mallard on NCIS and the mysterious Russian-born American secret agent Illya Kuryakin on The Man From U.N.C.L.E., passed away on Monday. He was 90.

A spokesman for CBS reported that McCallum passed away at NewYork-Presbyterian Hospital from natural causes while he was surrounded by family.

“He was the kindest, coolest, most patient, and loving father. He always put family before self. He looked forward to any chance to connect with his grandchildren, and had a unique bond with each of them,” his son Peter McCallum shared in a statement on behalf of the family. “He and his youngest grandson, Whit, 9, could often be found in the corner of a room at family parties having deep philosophical conversations.”

In addition, McCallum co-starred with Joanna Lumley for four seasons on the British sci-fi show Sapphire & Steel (1979–1982), which many consider to be a forerunner of The X-Files. He also portrayed a British prisoner of war in the classic 1972–1974 BBC drama Colditz.

From May 1957 until she left him for tough actor Charles Bronson ten years later, McCallum was wed to British actress Jill Ireland. However, McCallum swiftly recovered and wed model Katherine Carpenter in 1967. His wife of 56 years has survived him.

The boyishly attractive actor played Ducky, the bowtie-wearing autopsy expert with a psychology degree acquired from the University of Edinburgh, for all 20 seasons and more than 450 episodes of NCIS.