The star is back and ready for action as spy-on-the-run Jason Bourne in 'The Bourne Ultimatum.'

To see live streaming video from the movie premiere, click here.

MATT DAMON is back in the field as amnesiac spy Jason Bourne in the third installment of the highly popular, globetrotting action franchise, in theaters August 3 -- and we've got him in our sights!

"[Bourne is] somebody who always makes the right decision, and always does the smart thing, and that's what I like about it, just as a fan of the movies," Matt tells ET's MARK STEINES. "There's a lot of smart writers and directors and producers sitting around for days going, 'What would be the smart thing to do here?' And then they figure it out, and Bourne does it in one second, you know?"

Based on the successful novels by ROBERT LUDLUM, 'The Bourne Ultimatum' picks up right where 'The Bourne Supremacy' left off.

"We tried to get all of the things that people love about the movies and the character," explains Matt, "but you're not seeing the same movie again."

A CIA-trained assassin who lost his memory during a top-secret hit, Bourne spent the first film ('The Bourne Identity') trying to figure out his true identity while evading deadly operatives bent on his demise. Bourne promised retaliation to Treadstone (the super-secret agency that created him) if it came after him.

In 'The Bourne Supremacy,' Bourne and his girlfriend Marie (FRANKE POTENTE) move from city to city in the hopes of remaining anonymous -- and staying alive. But the CIA operative is discovered by a Russian assassin -- and Marie is killed in the crossfire -- compelling Bourne to take the fight to Treadstone's doorstep, no matter what the cost.

Now, in 'The Bourne Ultimatum,' Bourne travels from Moscow to Tangier, Paris, Madrid, London and New York City in a quest to find the real Jason Bourne, while police, federal officers, Interpol agents and Treadstone operatives JOAN ALLEN and JULIA STILES attempt to track him down -- and take him out.

Matt says that despite his best efforts to find peace and quiet in remote locales when not working, there'd be no escape if the authorities wanted to track him down.

"I was just on vacation with [BEN AFFLECK] and his family, and the first day we took a surf lesson at seven in the morning on this abandoned beach," recalls Matt, "and there were guys hiding in the shrubs taking our picture. So, as slick as I think I am, even they can find me, so I'm sure if the CIA wanted to get me they'd probably get me pretty quick."

Now a family man himself with a new wife, daughter and step-daughter, Matt found this third go-around a little tougher on the body than previous efforts, when he could focus all his off time in the gym.

"It's just a different thing; I have kids now ... I have a life at home I want to go to," he says. "I could really feel it in the fight scenes. I was just stiff, and I'd get up and I'd need to pop some Advil, you know?"

Matt has said in previous interviews that this may be the last 'Bourne' adventure for him, and unless another 'Ocean's' movie comes along soon, maybe it's time to don a pair of superhero tights?

"I think all the superheroes are gone, aren't they? I mean, who's left?" he ponders. Then, suddenly, it comes to him. "Aquaman. Yeah, that's the only one left."

Surf's up?!

Watch ET for more with Matt!