The NCIS and NCIS: Origins universes will collide once again during season 2 with a tribute to the one and only Ducky. Adam Campbell, who played Young Ducky on the flagship series, is set to reprise his role on an upcoming episode of NCIS: Origins, CBS announced on Thursday, August 28. The fall episode will double as a tribute to the late David McCallum, who portrayed fan-favorite Dr. Donald "Ducky" Mallard on NCIS for 20 seasons. (Campbell, meanwhile, played the younger version of Ducky on four episodes of the original series from 2014 to 2020.