More from alleged eco-hero Leonardo DiCaprio: Just this one article places him in South Africa, Cannes, Tokyo, Paris and Rome

‘Since I was a kid I’ve been passionate about different species being pushed into extinction and that propelled me to request a meeting with Al Gore in the White House. He said to me, “There’s this thing called global warming and it’s going to come to fruition in a horrific way in our future so if you’re going to get behind any issue, this is the one to get behind.”’

Since then, DiCaprio has become the most vocal and committed of Hollywood eco-activists. In 2000, he gave an impassioned speech challenging the incoming President Bush to pay attention to the issue.

And last year he premiered his full-length documentary feature on the state of the planet, 11th Hour, at the Cannes Film Festival. It had a mixed reception and DiCaprio was criticised for the perceived opulence of his jet-set lifestyle.

‘Just to clarify,’ he says. ‘I flew commercial.’

Despite his environmental campaigning, DiCaprio insists he is not the Hollywood poster child for all things green.

‘This is not about me,’ he says. ‘And it’s not about one group of people telling any other group of people how to live. I don’t think it’s fair to tell people to install solar panels, buy (low-watt) light bulbs or drive a hybrid – that’s not a reality for most people.

'It is about something much, much bigger. It’s about getting the governments of the world to implement environmental policy.

'We are the most powerful country in the world and we haven’t made a tiptoe towards renewable technologies. We should be the ones paving the way, the ones other countries look up to. It makes me extremely sad.