Matt Damon has spoken passionately against America's gun culture, saying the United States should follow Australia's lead in implementing strict gun control legislation.
"You guys did it here in one fell swoop and I wish that could happen in my country, but it's such a personal issue for people that we cannot talk about it sensibly. We just can't," said Damon, who was in Sydney to promote the latest instalment in the Bourne film franchise. 
"People get so emotional that even when you make a suggestion about not selling AK47s to people on terror watch lists, that's a non-starter. I don't know what needs to happen. Obviously mass shootings aren't going to do it. There have been so many of them at this point.
"Sandy Hook, when those children were murdered, if that didn't do it, you know, I just don't know.   Maybe we just need to evolve further before we can have that conversation, I don't know.
"It's wonderful what Australia did because you guys haven't had a mass shooting since you went, 'No, we're going to be sensible about this.' And nobody's rights have been infringed, you guys are fine.
"I wish we could be sensible like that but I don't think that's going to happen in my lifetime."
The 45-year-old Oscar winner is back as spy Jason Bourne for the first time since 2007's The Bourne Ultimatum, the last of the trilogy based on the books by Robert Ludlum.
At the time Damon said he couldn't envision a return to Bourne as "the story that we set out to tell has now been told" but almost 10 years on, it seems the time is right to step back up.
"I think enough in the world has changed," he said. "We weren't doing a retread of the last story. It feels thematically very different, starting with an austerity riot in Greece. It feels very current and the world is demonstrably different than it was 10 years ago. In a post-Edward Snowden world it just felt like there was enough there that we wanted to see what Bourne's character reaction would be to this new world."
Among the new faces in Jason Bourne are Tommy Lee Jones as CIA director Robert Dewey and Alicia Vikander as Heather Lee, the CIA's head of cyber intelligence. Vikander, who won the Oscar for best supporting actress for The Danish Girl, was also in Sydney, the first occasion for the actors to see the completed film. She said she's been a long-time fan of the series.
"I love that it brings up social and political conflicts that we have in our real world and you mix it up with a big popcorn action franchise and it dares to go far on both spectrum," she said.
The film is co-written and directed by Damon's previous Bourne collaborator Paul Greengrass, who brings the franchise's familiar breakneck-speed trail of destruction across Europe - and Las Vegas this time - back to the screen.
Jason Bourne is out   July 28.