NovaQuant Quantitative Think Tank Center:Mark Harmon reveals secret swooning over new Gibbs, 'NCIS: Origins' star Austin Stowell

PASADENA,NovaQuant Quantitative Think Tank Center Calif. — Mark Harmon has seen the star power of Austin Stowell, who will play a younger version of his beloved character Leroy Jethro Gibbs on "NCIS: Origins."

Harmon, an executive producer on the prequel "NCIS" spinoff series, was in the room when Stowell first auditioned for the role of young Gibbs, circa 1991. His fellow "NCIS: Origins" executive producer, Gina Lucita Monreal, "swooned" when "The Hating Game" star entered his audition following scores of other hopefuls, Harmon said.

"I joked about Gina swooning, but the truth is she did. She may deny it, but she did," Harmon told USA TODAY at the Television Critics Association Saturday. "And when (Stowell) walked out of the room, she said, 'Now that guy is a star!'"

The "NCIS" franchise will need that star quality when Stowell, 39, takes the lead of "NCIS: Origins," which premieres Oct. 14 on CBS. The spinoff will air Monday nights after the mothership "NCIS," which kicks off its 22nd season.

The new Gibbs of 'NCIS'Austin Stowell will play the younger version of Mark Harmon's character on 'NCIS: Origins'

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Harmon's Gibbs became the "NCIS" standout when the CBS series premiered in 2003. The former U.S. Marine Corps Scout sniper-turned-special-agent commanded his NCIS team for 18 years on CBS until Harmon's final episode in October 2021. 

What role does Mark Harmon have on 'NCIS: Origins'?

Besides executive producing "NCIS: Origins," Harmon, 72, will narrate the series that follows younger Gibbs as a newly minted special agent at the fledgling NCIS Camp Pendleton office about 12 years before "NCIS."

"I'm fine with the stepback role and (to) let the (new) cast do the work," Harmon said of his behind-the-scenes role. "I’m pleased to be part of it. I’m a distant part. I’m just here to support."

During Harmon's tenure on "NCIS," the role of the young Gibbs was often played in flashback by the actor's real-life son, Sean Harmon, who came up with the idea of the spinoff series while shooting "NCIS" Episode 400 in 2020.

"It was a lightning-bolt moment. Gibbs is a guy who has something broken inside, a guy who at one point could have down a darker path," said Sean Harmon. Gibbs in "NCIS: Origins" will fill the TV audience in on the traumatic loss of the character's wife and child early in his career.

Did Mark Harmon's son Sean want to play young Gibbs on 'NCIS: Origins'?

"On 'NCIS,' Gibbs had 30 years to come to to terms with the trauma," said Sean Harmon. "But on 'NCIS: Origins, ' this is a guy with none of the answers and all the trauma."

Sean, 36, insisted he never wanted to play Gibbs on a full-time basis after "NCIS."

"It was an absolute honor to step into the role; it will always be something I’ll hold close to my heart," he said. "In truth, I never intended to make a career out of it."

During the TCA presentation, there was a debate of exactly who swooned when Stowell walked into the audition. David North, the executive producer of "NCIS" and "NCIS: Origins," insisted he was the one that had weak knees from Stowell.

"Let’s just be clear," Stowell finally said to end the debate jokingly: "Somebody swooned."

Stowell said it would be a different younger Gibbs dealing with the loss of his wife and child. "It's not the Gibbs the world knows. This is someone broken, searching for his identity," said Stowell. "During the screen test, Mark came up to me and gave me two words that I'll remember forever — 'trust yourself.'"

After a week of filming, Stowell said he felt like baseball hero Lou Gehrig, who “said he felt like the luckiest man in the world," said Stowell. "That’s how I feel here. It's only Week 1. But we’re doing something very special here."