For years, NCIS fans wondered whether Mark Harmon was truly finished playing Leroy Jethro Gibbs.

Now they have their answer.

Harmon is stepping back into Gibbs’ world in a much bigger way for Season 3 of NCIS: Origins — and the first look at his return makes it clear this isn’t simply a quick cameo.

The new season brings viewers back to present-day Gibbs, years after he walked away from his old life and settled into a quieter existence in Alaska.

But that peace may be about to disappear.

CBS has revealed that Harmon will appear throughout the entire season as part of a present-day mystery connected directly to events from Gibbs’ younger years at Camp Pendleton.

And that’s what makes his return particularly intriguing.

The Season 3 premiere, titled “Don’t You Forget About Me,” finds something from Gibbs’ past finally catching up with him, threatening the peaceful retirement he built in Alaska.

The story will then move between present-day Gibbs and the younger version of the character, played by Austin Stowell in the early-1990s timeline.

For longtime viewers, seeing Harmon back as Gibbs carries another layer of nostalgia.

For nearly two decades, his quiet intensity, famous rules and unmistakable stare helped turn Gibbs into one of television’s most recognizable characters.

Now, after years away from the center of the action, Gibbs has another story to tell.

And this time, something from his past may be powerful enough to pull him out of retirement.

NCIS: Origins Season 3 premieres October 6 on CBS.