Matt Damon has criticised the selection of Republican vice-presidential nominee Sarah Palin as a "disaster".
The nomination of the Alaska governor as John McCain's running mate for the US presidency has caused much controversy, with questions over her experience, right-wing beliefs and the political motives of her appointment.
And speaking to the Associated Press news agency, Damon has expressed his fear that, should Mr McCain win the election, Ms Palin has a significant chance of becoming president, due to the Arizona senator's age and history of health problems.
"I think there's a really good chance Sarah Palin could be president, and that's a really scary thing," The Bourne Identity actor said.
The actor expressed his anxiety over the American public's lack of knowledge about Ms Palin's track record - other than she was the mayor of a small town and has been Alaskan governor for less than two years - and said her nomination had been made for "political purposes".
"In terms of governance, it's a disaster. You do the actuary tables, there's a one out of three chance McCain doesn't survive his first term and it'll be President Palin," he continued.
"It's like a really bad Disney movie. The hockey mom, 'I'm a just a hockey mom from Alaska', and then she's the president and facing down Vladimir Putin and using the folksy stuff she learned at the hockey rink. It's totally absurd.
"I don't understand why more people aren't talking about it. It's a really terrifying possibility and we're that close to this being a reality is crazy."
He went on: "I need to know if she really thinks dinosaurs were here 4,000 years ago, because she's going to have the nuclear codes. I want to know that, or if she banned books, or if she tried to. We can't have that."