In the role of former NCIS lead Leroy Jethro Gibbs, Mark Harmon is a tough act to follow. But it seems he found a worthy successor in NCIS: Origins star Austin Stowell.

LONDON -- Once again, Austin Stowell is having the best day ever — all thanks to him winning the role of legendary TV character Leroy Jethro Gibbs in “NCIS: Origins.” “Since I got this job, it has just been day after day after day of the greatest day of my life,” says Stowell, smiling.

Even the "NCIS" origin story for Austin Stowell has a Cracker Jack opening. The impossibly rugged actor, 39, had tried to clear his mind after his February audition for "NCIS: Origins," the prequel series to the CBS police procedural (premiering Monday,

NCIS: Origins is telling a story about Leroy Jethro Gibbs ( Austin Stowell in 1991, Mark Harmon narrating and briefly appearing in the premiere) that fans are completely in the dark about—and we start getting teases about that in the two-part opener.

Austin Stowell is single — and not ready to mingle — after the debut of his NCIS prequel series, NCIS: Origins. “I'm in a relationship with a TV show," Stowell, 39, joked to People on Monday, October 14,

NCIS: Origins' brings the early days of "Gibbs" back to the screens. Mark Harmon talks about the casting of Austin Stowell for the role of young "Gibbs".

Origins" was no easy task, but Mark Harmon was immediately impressed when Austin Stowell auditioned for the prequel.

Austin Stowell won the coveted role of young Leroy Jethro Gibbs on NCIS: Origins. Stowell portrays the role made famous by Mark Harmon on NCIS, but you may have seen him in some other high profile roles over the years.

NCIS: Origins, a prequel to the long-running CBS series NCIS, premiered on the network on October 14. The show focuses on the younger version of Leroy Jethro Gibbs as he begins his tenure as a special agent of the Pendleton branch of the Naval Investigative Service (NIS).