Sean Harmon NCIS: How is Young Gibbs star related to Mark Harmon?

NCIS will air its 400th episode on November 24 with a special episode focused on how Leroy Gibbs (played by Mark Harmon) and Donald ‘Ducky’ Mallard (David McCallum) met. This will include a number of flashback scenes where Sean Harmon and Adam Campbell will reprise their roles as younger versions of the characters. However, fans may be surprised to know how Sean is related to star Harmon.

How is Sean Harmon related to Mark Harmon?

Fans of NCIS have been looking forward to the special anniversary episode of the show ever since it was postponed from season 17.

Now it will finally be airing as part of the eighteenth series and will be entitled Everything Starts Somewhere.

The landmark episode will tell the story of how Gibbs first met Ducky.

This will involve flashbacks to these moments, meaning fans will be able to see younger actors take on the roles once again as well.

READ MORE: NCIS: Why did Gibbs shoot McGee in NCIS season 18 premiere?

He also played Charlie Connor in a 2015 episode of NCIS: Los Angeles as well.

Viewers will next see him as Jones in the television film Thicker, which is due out in 2021.

Harmon recently opened up about what it is like to have his son on the show with him.

Speaking to Entertainment Tonight about Sean reprising the role, Harmon revealed how proud he was.

He said: “I always think back to the first time they talked about doing a young Gibbs thing here, and Sean was just out of school at that point.

“A director named Tony Wharmby said, ‘Can he come in and read?’

“And on his own he did and I’m proud of him taking his work seriously and how he approaches being an actor.

“Not just on this show, [but] just what he has chosen to try to do in his life’s work.

“I’m proud of both our boys, and they work hard at what they do and I’m proud that they get up in the morning and try to do that every day.”

He also revealed to the publication how his wife Pam Dawber is also excited for Sean.

Harmon added: “More than anything, she’s a mom, and there’s a pride there involved in that.”

NCIS season 18 airs on Tuesdays on CBS.