Leonardo DiCaprio dives into world of dreams
Christopher Nolan's new film Inception is a blockbuster with brains.
Even its star Leonardo DiCaprio admits it's not a script he managed to grasp first time round.
"It took multiple reads," says DiCaprio. "But it really was about being able to sit down with Chris Nolan and delve into his mind."
Inception is Nolan's cerebral sci-fi follow-up to his Batman epic The Dark Knight, which has made more than $1bn (£652m) at the global box office.
Inception sees DiCaprio as Dom Cobb, the leader of a team of thieves who raid secrets from other people's dreams. The cast includes Sir Michael Caine, Ellen Page, Cillian Murphy and Marion Cotillard.
With much of the action taking place within dream worlds, there is plenty of scope for some eye-popping set-pieces.
A freight train appears out of nowhere on a busy Los Angeles street. A whole city folds itself over like a paper napkin.
Even for a film set in several dream worlds, Nolan kept computer trickery to a minimum.
In one scene, DiCaprio and Ellen Page (playing dream architect Ariadne) are sat outside a Paris cafe when the whole street explodes around them. The actors were right in the middle of it.
"We were there," confirms DiCaprio. "He doesn't use a lot of green screen - he's a very cutting-edge film maker, but he's very old school in his approach. He immerses his actors right into those environments and makes you react as if you were there."
Some of the sets were built to revolve and tilt to achieve some of the film's zero gravity sequences. How did DiCaprio find being thrown around?
"There was a long dialogue between Cillian and myself - four or five pages - and the whole set was on hydraulics. It gave a whole sense of urgency to the scene.
"Normally if we're just looking at floating green balls and a blue background we'd feel differently, but literally he put the whole set on an axis and we had to hold on for our lives while we were performing."
Signing up to Nolan's project sent DiCaprio off to the library.
"A lot of these concepts and these visuals have been stirring around in his mind for the last 10 years, so I tried to take a really traditional approach to researching this project - and read about Freud and the analysis of dreams.
"But I realised this was Chris Nolan's dream world and I needed to tap into his mind."
DiCaprio has worked with some of the greatest directors on the planet: Martin Scorsese (Gangs of New York, The Aviator, The Departed, Shutter Island), James Cameron (Titanic) and Steven Spielberg (Catch Me If You Can).
So how was his debut with Nolan? "There's a certain calm and ease that he has," says DiCaprio.
"You'd think that someone who's been able to pull of such ambitious high concept films would be frenetic and mad, but the man simply knows what he's doing.
"I remember watching Memento and Insomnia years and years ago and being fascinated by the multi-dimensional plot structures that unfolded before my eyes."
Reviews for Inception have bordered on the ecstatic, with many drawing attention to its intellectual depth.
DiCaprio says he's seen plenty of "regurgitated plot structures" in summer blockbusters.
"It's nice to see films like this and other films which come out that take a gamble a little bit, and don't underestimate their audience, and challenge them."
Some of Inception's action sequences clearly owe a lot to James Bond. Nolan has admitted 007 was a big influence.
With the Bond franchise in uncertain territory, how does DiCaprio feel about stepping into Daniel Craig's secret agent shoes?
"I think he's doing a terrific job," laughs Dicaprio. "I wouldn't dare think of that at this moment. I think he's an excellent Bond - don't you? - I think he's fantastic. You guys should be very proud!"
Inception is released in the UK on 16 July.