The actor sat down with Sky News to talk about his new thriller Shutter Island, but first there was the small business of asking how he felt now that Avatar has sunk Titanic to become the highest grossing film ever made.

"I hear there was a big discussion about whether it was going to take over the Titanic number," laughs Leo. "To be honest I don't really pay attention to those types of things until it hits the headlines.

"But God speed to that movie because I thought it was an incredible experience. James Cameron has been able to tap into what audiences want to see on a worldwide level."

Shutter Island sees DiCaprio team up with legendary director Martin Scorsese for the fourth time in an adaptation of the famously dark and cryptic novel.

The meditation on mental illness is so full of twists and turns it seems almost impossible to explain without giving too much away.

"It is, and it's even harder to publicise," Leo smiles, before giving it his best shot. "It's a giant complex jigsaw puzzle that you have to slowly piece together, along the way you don't know who to trust.

"All that mixed with Martin Scorsese taking on a Hitchcockian genre and a gothic horror. It's a fun ride!"

Shutter Island has already done huge business in the States, but DiCaprio is just happy to have racked up film number four with the man behind the lens, whose legacy includes classics like Taxi Driver, Raging Bull and Goodfellas.

"I've been fortunate enough to work with the person who I believe is the greatest filmmaker alive and there's not many people you can say that about without smirking," says DiCaprio.

"I've been working with him for 10 years now, and we share the same tastes. We definitely know what we hate and that's extremely important I think."

The fact that Leo seems to have replaced Robert De Niro as Scorsese's leading man of choice suggests that every script the director now gets comes to DiCaprio first.

It's as if they have a magic Bat-Phone hot wired between their homes.

"No Bat-Phone, but that would be cool," Leo smiles. "He keeps redefining himself as an artist, and so if he calls me up for a role I'm immediately excited, and I'm a fortunate young man.

"Although I'm not a young man any more now, I was when I started with him!"