Hartnett was close to retreating from Hollywood and returning to his native Minnesota when he agreed to sit down and chat to Nolan about his Batman project and now he realises he should have taken the role, because snubbing the revered filmmaker was a very bad idea.

The actor tells the new issue of Playboy, "I’ve definitely said no to some of the wrong people. People don’t like being told no. I learned my lesson when Christopher Nolan and I talked about Batman. I decided it wasn’t for me. Then he didn’t want to put me in (2006 film) The Prestige.

"That’s when I realised relationships were formed in the fire of that first Batman film and I should have been part of the relationship with this guy Nolan, who I felt was incredibly cool and very talented.

"I was so focused on not being pigeonholed and so scared of being considered only one thing as an actor. I should have thought, 'Well, then, work harder, man!'

"Watching Christian Bale go on to do so many other things has been just awesome. I mean, he’s been able to overcome that. Why couldn’t I see that at the time?"

Hartnett admits that his time away from Hollywood has magnified some of the mistakes he made in his early career.

He explains, "Fame can be a dangerous thing. It can destroy you. I used to put myself in positions where I spoke up when I probably should have been listening. When you're young and have convictions, and fame suddenly gives you a microphone, you think, 'I'm going to tell everybody how it is'. I had to take a step back from doing that to figure out, 'Do I actually know what I’m talking about?'"