The star tells The Hollywood Reporter how 'NCIS' helped lead him to co-author his second book, 'Ghosts of Panama,' while also balancing TV work and the upcoming 'Freaky Friday' sequel.

Origins takes place in 1991, the prequel that’s currently airing on the 2024 TV schedule chiefly serves as a platform for Austin Stowell to play the younger Leroy Jethro Gibbs. However, Mark Harmon, who played Gibbs on NCIS for nearly two decades,

When Mark Harmon wrapped up his role as Leroy Jethro Gibbs on NCIS, he didn’t have a clue that he was going to return to narrate the voiceover on a prequel series, NCIS: Origins, that tells Gibbs’ story and that of Mike Franks.

Austin Stowell exclusively told Us Weekly about Mark Harmon's immediate response to his 'NCIS: Origins' performance as Gibbs

The reveal of what Gibbs is doing in 2024 was one of many Easter eggs that has been part of the launch of Origins. Others include Gibbs getting his first sip of bourbon, the first time he stopped an elevator for a private conversation, the fact that he always carries a knife, and more info on how Gibbs’ rules came to be.

Origins episode “Incognito” featured an unexpected appearance from a younger Tobias Fornell, whom Joe Spano has been playing on NCIS since it began in 2003, and whom Lucas Dixon is playing in this CBS prequel.