As the premiere date for the NCIS prequel, NCIS: Origins, looms, you may wonder if you need to watch the original to understand the prequel. NCIS: Origins will explore the backstory of the central NCIS character, Leroy Jethro Gibbs, played by Mark Harmon in the flagship NCIS series for 19 years. Harmon established a robust presence as Gibbs during his era with the series, and while the actor can’t reprise the role, Harmon will return to narrate the series. In the prequel, Austin Stowell plays Gibbs, and his characterization promises a more vulnerable character representation.