Mark Harmon will reprise the role of Leroy Jethro Gibbs in an upcoming episode of “NCIS: Origins.” Harmon, who played Gibbs for 18 seasons on “NCIS,” is the narrator of “NCIS: Origins,” but a Veteran’s Day crossover event will mark his first on-screen appearance since the prequel series’ 2024 pilot.

The original Leroy Jethro Gibbs is about to make a comeback. Mark Harmon is set to reprise the role he played for 18 seasons during the first crossover event between NCIS and NCIS: Origins set for Nov.

Mark Harmon is making an on-screen return to the NCIS universe. Harmon will guest star in an episode of NCIS: Origins on Nov. 11, reprising his longtime character Leroy Jethro Gibbs. The episode will be part of a crossover with NCIS,

"NCIS: Origins" will catch up with present-day Leroy Jethro Gibbs as part of its big crossover with the flagship series in November. Franchise legend Mark Harmon is set to make a special guest appearance in the Nov.

Mark Harmon will appear as Gibbs ("and he's no longer alone!") in the Nov. 11 episode of "NCIS: Origins," part of a crossover event with "NCIS."

Origins crossover even more special: Mark Harmon is reprising his role as Leroy Jethro Gibbs in the first hour. CBS announced the news of Harmon’s special guest appearance on NCIS: Origins during the crossover on Tuesday,