Off-screen, Mark Harmon, who left the show in 2021, has two sons: Sean and Ty. The former has even followed in his dad's footsteps by appearing in several NCIS episodes as a younger version of Harmon's character, special agent Leroy Jethro Gibbs.

This will be Stowell’s first episode working with Campbell; the actor played young Ducky in four NCIS episodes, and on the mothership, young Gibbs was played by Sean Harmon (who is an exec producer on Origins ). “Ducky is undeniably charming, able to win over the grumpiest of grumps,” notes Stowell.