Did you have any reservations about working with CGI dragons?

My initial thoughts were that it could have become a special effects project rather than an acting project. I was worried that it might end up with the people in it looking a little bit foolish. Also, I was concerned about how the dragons were going to look.

CGI is an incredible thing but I've seen them use it disastrously many times before. But, that said, I'm kind of attracted by movies where there is a real possibility of it going badly wrong. There have been movies where other people have said to me "You're nuts for doing this! Why would you risk doing this?", and I've kind of realized that that's what I enjoy.

What about the head butt from Matthew McConaughey during the big fight scene?

It dropped me like a sack of potatoes. In the movie you see me crawl around the ground for a couple of seconds to try to find my bearings - that is real! Then I thought I had to get up and finish the scene or it was going to be no use.

I could see that the film crew were staring to see if I was all right. When we finished I asked Matthew if he was OK. He said "Yeah, you mad bastard - I headbutted you!"

There are rumours that you have a love/hate relationship with acting...

I started at a young age and some of my memories that I think of as my life are not my life. They are scenes that I was in. It is a very sad state of affairs. I'll find myself having dinner with people and someone will mention something and I will say I was in that situation once. Then I'll say, forget it, it was a scene I was in. That can get to be quite confusing.

Did you go out much in Dublin when you were not working on Reign Of Fire?

I am not a big social animal, especially when I'm working. I feel really silly acting in front of other actors if I feel I know them too well. I don't want people to be able to tell how much I am acting.

We went out in Dublin a few times and Matthew had parties at his place, but most of the time he was down at the boxing gym - sparring and just hitting somebody.