Mark Harmon will always be an integral part of NCIS.
The Freakier Friday actor was part of the inaugural cast in 2003, as Special Agent Leroy Jethro Gibbs.
And though he left the show in 2021, his legacy has remained steady, through his work as an executive producer, through the prequel series NCIS: Origins, and now, via a secret tribute in another upcoming spin-off.
Come this September 4, the long-awaited Michael Weatherly, Cote de Pablo spin-off NCIS: Tony & Ziva, which focuses on their characters Anthony DiNozzo and Ziva David, will arrive at Paramount+.
Per EW, the on-screen couple, during an appearance at San Diego Comic-Con 2025, made a special gesture at each other: arms raised, fists balled and swiveling on their hinges as if knocking on a door with quizzical "I got this" expressions on their faces.
The move came after they previewed the first ten minutes of the pilot episode; their old NCIS co-star Brian Dietzen was there, and asked what that was, to which Cote and Michael responded in unison, "Mark Harmon."
"This is his sign language thing from an episode," Michael added, as Cote called it "such a great moment."
She further explained how the gesture is a tribute to Gibbs, who used it to communicate with them on a bus together, and they have replicated it since. "I think we were in a school, right? On a bus. There was a camera, and he was sort of communicating with us. He felt no one was watching him. So since that moment, every time Michael and I — we could be anywhere in the world — and I'll just go [performs the hand gesture] and we know."
The forthcoming premiere of Tony & Ziva, NCIS' sixth spin-off, comes 10 years after Michael's departure as a series regular, and 12 after Cote's.
The show will spotlight their characters as they raise their daughter Tali DiNozzo (played by Isla Gie) and explore their "unconventional love story," and the other storylines centering around their adventures in Europe.
And though NCIS and its spin-offs has typically been given a PG-13 rating, Tony & Ziva has instead been given a TV-MA rating, meaning for mature audiences only, possibly indicating that the show will go even further than the original when it comes to graphic scenes or, potentially, as some fans have speculated online, more mature content between its leads.
TVLine addressed as such in a recent story addressing the rating, however the publication claimed that some of the rating can instead be attributed to more graphic language, specifically from Cote's Ziva. "Having screened the streaming spinoff's first four episodes, I will reveal this much: you may not realize how much you needed to hear a ticked-off Ziva swear," their report read.