Actor David McCallum, known for his role as Dr. Donald "Ducky" Mallard on the TV show NCIS, has passed away at the age of 90. He died peacefully at New York Presbyterian Hospital from natural causes, surrounded by his family. McCallum was remembered as a loving father and grandfather, as well as a talented and knowledgeable actor. The executive producers of NCIS described him as a scholar, a gentleman, and a legend. CBS expressed sadness at his passing and honored his legacy. A marathon of NCIS episodes will now include a tribute to McCallum.