It's been 15 years since Colin Hanks' breakout role in Orange County, and the 39-year-old star is still grateful.

"I'm really proud of that movie," Hanks tells ET. "I'm really proud of the people I made it with and I had a really fun time. And the fact that anybody is talking about something you did 15 years ago, that's very special. It's not lost on me. I'm so happy that the people who saw it when it came out still remember it, and there's a whole other generation of people that have seen it since and dug it just as much."

Hanks went on to tackle memorable roles -- from the hilarious to the dramatic, in The House Bunny, Dexter, Fargo, and many more -- over the years. In 2015, he made his directorial debut with All Things Must Pass, a telling documentary about the rise and fall of the iconic Tower Records.

WATCH: Colin Hanks on the 'Motley Crew of Characters' That Inspired 'All Things Must Pass' 

Now he's back in the director's chair for his latest doc, Eagles of Death Metal: Nos Amis (Our Friends), airing on HBO Feb. 13.

The film follows his longtime friends, musicians Jesse Hughes and Josh Homme, as they returned to Paris for a performance following the horrific terror attack on the Bataclan theatre.

"I wasn't about to let them go through this thing alone," he explained at the film's premiere on Thursday night at the Avalon in Hollywood, California.

Hanks says the film "transcends what the subject matter is, and is really a story about friendship and people who care about each other."

Coincidentally, Hanks had another longtime pal in the audience to show support on Thursday night -- his Orange County co-star, Jack Black.

"We're friends for life," Hanks gushed.