Adam Campbell's return to the NCIS universe as young Donald "Ducky" Mallard on NCIS: Origins will pay homage to the OG character - and drop a few easter eggs for fans of his and Gibbs' friendship. "This episode is about the rekindling of old friendships between Gibbs and Ducky," Campbell, 45, exclusively told Us Weekly on Thursday, October 23, of his upcoming guest appearance on the CBS show. Fans were initially introduced to Ducky (played by the late David McCallum) as the medical examiner on NCIS in 2003, where he worked alongside Special Agent Leroy Jethro Gibbs (Mark Harmon).