George Clooney has denounced Donald Trump as a "xenophobic fascist" and forecast that American voters will reject his "crazy" campaign for president in November.

The star used a quote widely attributed to Winston Churchill in predicting the frontrunner's eventual electoral defeat.

"You can count on Americans to do the right thing after they've exhausted all the other possibilities," he said.

Of Trump's political beliefs, he said: "He's just an opportunist. Now he's a fascist; a xenophobic fascist."


Clooney told the Guardian he supported Hillary Clinton's bid for the presidency, although he heaped praise on the campaign of her rival, Bernie Sanders, whom he said had raised topics often ignored in US politics, like income inequality.

"I am a Hillary supporter. I am doing a fundraiser for her," said the actor, who raised US$12 million ($18 million) with a single event for Barack Obama's 2012 campaign. "I really love Bernie Sanders, and I am really glad he is in the debate. He is forcing the conversation to things that never get talked about in US politics: disparity between the rich and the poor, which is getting worse and worse every day."