Matt Damon Returns as Former CIA Assassin in Latest 'Bourne' Film

Matt Damon poses for photographers upon arrival at the European premiere of the film 'Jason Bourne' in London, July 11, 2016.

Actor Matt Damon returns as a troubled former CIA assassin in the latest edition of the hit "Bourne" movie series this month, reprising a role he says was physically tough to get ready for over a decade and a half since he first took it on.

"Jason Bourne" - the fifth installment of the franchise - hits movie theaters on July 27, starring Damon as a conflicted, restless hero who resurfaces at the Greek-Macedonian border a decade after going off the grid.

At the movie's European premiere in London, Damon said it was a "lot of fun" to be back in Bourne's shoes as he returned to work with familiar faces. But physically - preparing for a movie that features intense fight scenes and a major car chase - was challenging, the actor said.

"It was hard to get ready for it, much harder than when I was 29 - I'm 45 now, so it's whole different animal," Damon, who sat out the fourth movie in the series, told Reuters on the red carpet. "But you know, that's a good problem to have."

Asked who would win a tussle between Bourne and another legendary cinematic spy, James Bond, Damon was non-committal.

But he had little doubt about who he would back as the next actor to play the MI6 spy: British actor Idris Elba.

"I like Idris - yeah, I think he's brilliant," said Damon. "I'll watch him in anything and he makes everything he's in better. He would make that franchise better."

In the latest Bourne edition - based on the novels by Robert Ludlum - co-star Julia Stiles returns as fellow operative "Nicky Parsons" while Alicia Vikander, a longtime "Bourne" fan herself, debuts as a prodigy hacker in the CIA director's team.

"The Bourne franchise was one of my absolute favorites - I'm a big fan," Vikander, dressed in a silver sequined dress, gushed on the red carpet. "It was a real pinch-me moment when I actually saw myself, saw the film for the first time a week ago and I was like 'Oh my God, I actually got to be in one of them!'"