Hollywood actor Kevin Costner has squandered more than £20million of his fortune on doomed investments to save the planet, he admits.
The Oscar-winning Dances With Wolves star plunged the cash into "green technology", forming two companies to develop his passion.
His first venture championed a revolutionary method to clean up major oil spills and the second tried to develop a successful non-chemical battery.
But both projects failed and he lost the entire investment.
He says in an interview in Live magazine: "I've invested enormous amounts in technologies I thought would help the world.
"There's nothing to show for the millions I've invested. My God, most people would want to die if they lost $1,000 or $100,000. I've lost $40million plus.
"But I knew that if I was right it would change things in an incredibly positive way. Do I regret that? Yes. Has it changed my life one bit? No, because I haven't been moved by money."
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