James MacArthur, best known for his role as Dan-O on Hawaii 5-0, has died at the age of 72 of natural causes. In this day and age, that's way too young.
He was the adopted son of Charles MacArthur and Helen Hayes. His godmother was Lilian Gish. He caught the acting bug and made it to Broadway. He did several roles for Disney and guest shots on TV before catching his big break on Hawaii 5-0.
Best wishes to his family and friends.