NCIS: Origins reveals first look at main cast – and young Gibbs is Mark Harmon's double

Austin, who is known for his roles in Bridge of Spies and Catch-22, leads the cast as Young Gibbs, a "newly minted" agent just starting his career. 

Caleb will play Special Agent Benjamin 'Randy' Randolf, the agency's "golden boy" who is tasked with showing Agent Gibbs the ropes. Viewers might have seen him in the TV series, Made for Love, The Kids Are Alright, and NCIS: Los Angeles.

Mariel portrays Special Agent Lala Dominguez, a former Marine with a dark sense of humor whose dynamic with Gibbs is "full of sparks". Could a romance be on the cards? 

Mariel has also appeared in The Watchful Eye and Promised Land.

Diany, who's best known for playing Weecha Xiu in The Blacklist, plays Special Agent Vera Strickland, who is described as "a no-nonsense, sharp-witted Brooklynite who's tough as nails and never minces words". 

Kyle takes on the role of Mike Franks, a "proud Texan who all but showers in his cowboy boots and sports a perfectly coiffed mustache that's as thick as his skin". The actor has previously appeared in Being Human and The Rookie.

Tyla stars as "mama bear" Field Operation Support Officer Mary Jo Hayes, who refers to herself as 'HSIC' — Head Secretary in Charge. Viewers may recognise the actress for her roles in The Chi and Shrink.