The prequel series brings multiple legacy characters from "NCIS" back into the fold. One of the foremost network procedurals, NCIS debuted on CBS in 2003 and has been rapidly expanding its franchise ever since.

Mark Harmon, widely known for playing Special Agent Leroy Jethro Gibbs on the hit CBS drama "NCIS," is stepping behind the camera as the executive producer and narrator of a new spin-off prequel, "NCIS: Origins.

Austin Stowell plays Leroy Jethro Gibbs, the beloved role created by Mark Harmon on 'NCIS', on CBS' new spin-off drama When Mark Harmon first read the guest role of Naval Criminal Investigative Service special agent Leroy Jethro Gibbs on JAG in 2003,

After nearly 20 years as Special Agent Gibbs, Mark Harmon is back in the NCIS world as executive producer and narrator of the new prequel, "NCIS: Origins," which stars Austin Stowell.