Leonardo DiCaprio’s celebrity friends and supporters were out at the premiere of his environmental film The 11th Hour in Hollywood yesterday. The documentary urges us to make a difference in the state of our planet now, in the 11th hour, as it’s almost too late. With existing technology and a concerted effort the film asserts that we can ensure that our planet remains sustainable. It’s not about saving the environment so much as ensuring the continued survival of the human race.

In an interview with Entertainment Tonight, DiCaprio explains that it takes him just 15 minutes to get ready for a premiere. He says the film explores how we can make a difference in our world and that by interviewing experts he thinks that 11th Hour explains it in a way that is unique while focusing on change:

“How long does it take me? Usually 15 minutes, something like that,” Leo says about getting red-carpet ready. “And then it’s about putting the suit on. I don’t have a stylist — usually it’s my assistant who tells me to put this on and I go, ‘Okay.’

But before Leo walks out the door, there’s one crucial tool he can’t forget: “What do I not leave the house without? My cell phone!”

As for the new movie, the award-winning environmentalist star gives ET the lowdown…

“It’s not just global warming, it’s not just a loss of biodiversity, it’s not just the pollution of our oceans and the clearing of our rainforests and all these complicated systems,” Leo tells ET. “[The movie] talks about the world economy, it talks about politics, it talks about personal transformation and environmental consciousness that we need to have in this generation to implement a lot of these changes that need to occur.”

The movie, which features Leo as narrator, explores what it will take for humans to make a difference ecologically before it’s too late. Top scientists like STEPHEN HAWKING and leaders like former Soviet Union President MIKHAIL GORBACHEV are interviewed for the documentary.

“It’s a very, very daunting issue and it was a lot to, as filmmakers, wrap our head around,” says Leo, “but thankfully we got some of the most important people in the forefront of a lot of these issues to really explain it in a way that I don’t think has been done before, and that’s what I’m proud of.”

[From ETOnline]

Here’s a clip especially created for YouTube with a preview from the film. The first expert who speaks really brings it home with this statement: “The environment is going to survive, we’re the ones who are not going to survive, or we may survive in a world we don’t particularly want to live in.”

Here’s the trailer for the film. It looks really moving.

The 11th Hour is out in theaters on August 17.

Pictured at the premiere are Leonardo DiCaprio looking like he’s lost a little weight, Kate Bosworth, looking healthy, and DiCaprio’s good friends and fellow environmentalists Tobey Maguire and Adrian Grenier. Thanks to WENN for these photos.