Mark Harmon, who portrayed Leroy Jethro Gibbs in NCIS for nearly two decades, revealed on the Kelly Clarkson show that his departure from the series in Season 19 was due to exhaustion. The actor, then 70, cited the demanding schedule, with 22-hour workdays on occasion, as a factor. Despite rumors about his motivation, Harmon expressed openness to returning to the iconic role. While CBS didn’t bring back iconic cast members for Season 20, Harmon’s Gibbs might make a comeback in Season 21, possibly in a tribute episode following the recent death of David McCallum’s character, Ducky. However, there’s no official word from CBS yet on Gibbs’ return.