David McCallum, Star of ‘NCIS’ and ‘The Man From U.N.C.L.E.,’ Dead at 90

David McCallum — who starred as pathologist Dr. Donald "Ducky" Mallard in NCIS for 20 seasons and Illya Kuryakin in the 1960s series The Man From U.N.C.L.E. — has died, according to Variety. He was 90.

McCallum died of natural causes surrounded by family at New York Presbyterian Hospital, per The Hollywood Reporter.

"He was the kindest, coolest, most patient and loving father," the actor's son, Peter, said in a statement to Variety. "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. He and his youngest grandson, Whit, 9, could often be found in the corner of a room at family parties having deep philosophical conversations."

"He was a true renaissance man — he was fascinated by science and culture and would turn those passions into knowledge," Peter continued. "For example, he was capable of conducting a symphony orchestra and (if needed) could actually perform an autopsy, based on his decades-long studies for his role on NCIS."

"After returning from the hospital to their apartment, I asked my mother if she was OK before she went to sleep," he added. "Her answer was simply, 'Yes. But I do wish we had had a chance to grow old together.' She is 79, and dad just turned 90. The honesty in that emotion shows how vibrant their beautiful relationship and daily lives were, and that somehow, even at 90, Daddy never grew old."

According to the New York Times, McCallum played a wide range of parts across theater, film and television, from Shakespeare's Julius Caesar in 2000 to the voice of Professor Paradox on the animated television series Ben 10: Ultimate Alien a decade later.

His role as Illya Kuryakin earned him two Emmy nominations in the '60s.

CBS — home of NCIS — acknowledged McCallum as a "gifted actor and author" who was "beloved by many around the world."

"We are deeply saddened by the passing of David McCallum and privileged that CBS was his home for so many years. David was a gifted actor and author, and beloved by many around the world," the network's statement read on X. "He led an incredible life, and his legacy will forever live on through his family and the countless hours on film and television that will never go away."

"We will miss his warmth and endearing sense of humor that lit up any room or soundstage he stepped onto, as well as the brilliant stories he often shared from a life well-lived. Our hearts go out to his wife Katherine and his entire family, and all those who knew and loved David."

McCallum published his novel Once a Crooked Man, an international crime thriller, in 2016.

McCallum was married to Jill Ireland from 1957 to 1967. They had three sons together. He married Katherine Carpenter in 1967 and were married for 56 years. They had two children, a son and daughter.