Josh Hartnett's new film, Wicker Park, is a tense psychological thriller about love and obsession taken too far. Life takes a strange turn when Josh's character, Matthew, thinks he catches a glimpse of his beloved ex, Lisa (Diane Kruger), who disappeared mysteriously two years before. Cancelling an important business trip and lying to his fiancee, he goes hunting for his missing love, only to stumble into the apartment of another Lisa (Rose Byrne) and the mystery unravels...

Rose Byrne's character in Wicker Park says 'Love makes you do crazy things'. Do you think people's actions are excusable when they're in love? Have you ever done anything crazy when you were in love?
Actions are excusable to the extent that they're legal. Of course I've done some crazy things. I think if you're in love and you're not doing something crazy then you're not really in love. Love is emotional, love is sometimes uncontrollable. There are varying degrees in this film of what love will make you do – there's a thin line between love and obsession. Some people will go to the ends of the earth for their chance at love. I think I'm more of a fatalist when it comes down to it, I believe love will find a way and I believe when something's meant to be, it's meant to be. Unless I was sure that the person I was in love with was in love with me also, I don't think that I would chase them.

Your character Matthew falls in love at first sight - do you believe in love at first sight?
I don't think there is love at first sight, I think that the spark that creates love, the spark of interest at first sight is what can turn into love – I believe in that. Love is too complicated, too layered an emotion to have right off the bat. If you did fall in love at first sight I think that would be too much, your heart would stop and you'd die. Love has so much to do about history, what you know about someone, what they've given you, what you can give of yourself. But that spark that creates it is ultimately there or it's not when you first meet someone.

Have you ever had, or been the subject of an obsession?
Well, I'm a film actor, so I get some weirdness sometimes. I've done some strange things, but nothing anywhere near those in the film.

In the beginning of the film Matthew seems like a guy who's resigned to his fate, it seems like you were trying to get a kind of hopelessness across…
What I wanted to do was to create a character who lost all his will to continue forward, to try anything new. Whose life is set at the point that you meet him – he'll do it, he'll live the life, he'll do everything the way it's supposed to be done, he'll be a nice guy, but he's lost all of his will to try something new because he's scared. He had his heart tossed back in his face and in a way that was almost perverse, Lisa just disappears. It's affected him hugely. He's lost.

What are the essentials you look for when you choose to make a film?
I try to choose by character. Before I was kind of going willy nilly, I wanted to try something in every genre and I wanted to see what I could or couldn't do, and I wasn't so worried about creating a career. I wanted to be open and try all sorts of new things. But now I've narrowed it down – I know what really sucks and what is fun. I want to work with good directors. The three things that are important are a good director, good script and a good character. I want to create good roles, because I know that I'm a pretty good actor.

Catherine Zeta Jones recently said that Hollywood was boring – what do you think of it?
I don't spend a lot of time there (Josh splits his time between Minnesota and New York). I think that anywhere with a singular focus is boring. I need all types of people around to enjoy myself. When I get done working I don't want to go to a place where all they talk about is work – who's doing what, or who's earning what or who's going to be the next big thing, it's kind of annoying. I'm trying to do smaller, more character-driven films. Hollywood, it's the business, and I wouldn't want to spend my life constantly around the business.

Do you go online?
Yes, but mostly to buy tickets or to get directions. Whenever I see things about me on the web they're all wrong! I wasn't born in San Francisco, I didn't audition for Dawson's Creek and I didn't save some woman from a mountain lion! Most of the time I'm playing on my Mac with iTunes or Photoshop. I'm an arts guy – I wanted to be a painter, that's what I did in college.