How much influence did your son have on you accepting the film? Did he visit the set?

Yes, he made it quite clear that if I didnt play the part, I would be dead.. Yes, he did come to the set and he spent a day as an extra. He absolutely loved the film. I have never seen him so absorbed in anything in all his life. He claimed he wasnt scared but he was terribly touched at al the mirror scenes. All his pretence at being cool quickly disappeared and thats when you are sure your kid is enjoying himself.

Did you feel any pressure or expectation with this role?

I had a letter from this woman just before we began filming. It started off really sweet and complimentary, as they usually do. She said that she had followed my career, told me she loved me, wanted my love children, etc , and then she said: I am really glad that you are playing Rubeus Hagrid because the expectations of millions and millions of children throughout the world are resting on your shoulders now So I thought :No pressure then?!

You have to give it your absolute best shot. Everybody in the film is aware of how important it was and what a big responsibility it was because most of the people on set were parents and had read the book to their children. It raised everybodys game.

What was your biggest kick during the making of the film?

I have to say how clever and incredibly brave these wonderful kids are. I have been doing this business for over 20 years and it still scares the life out of me. You think: This costs  £500 million, so I better get it right. These kids coped really wonderfully with that and they were so much fun to work with. Its the nicest feeling going to the set to enjoy yourself. I dont think Ive ever worked on a set with so much money involved and so much pressure. But Chris (director) knows how to run a happy set. There are usually guys in shiney suits hanging around looking nervous. I am sure he probably had that, but it was all kept out of sight. It was a very, very happy set.

You know people always say: So tell me something hilarious that happened on set Robbie?, and you can never remember anything. I do remember when we were filming in the forest late at night and a group of cyclists rode past. I was in costume, looking about 9 foot tall and another actor was dressed up fully as a unicorn .. The circus had come to town. Then four enthusiastic yuppies, dressed in proper equipment with lights on their helmets, came flying down the set. What would they tell their colleagues on Monday?: Well on Sunday night, we were going through the forest and there was a 9 foot bloke, a dead unicorn and these huge lights everywhere.. Their colleagues would have to call the medics straight away. One of the cyclists nearly fell off his bike he was so shocked.

Did you worry about working with children and did you provide them with any advice?

I didnt have to tell them anything at all. All the other actors instinctively managed to make the younger ones feel at home. We were all mucking around and joking. Theres a great myth about  working with animals and children. Young people sometime have a problem, with thier emotional memory. And, unless you have somebody like Chris, who is wonderful children and knows how to put them in that particular place where they can remember their emotion, then you wont get through to them. Even two emotions conflicting with each other is hard enough for us adults. With Chris, we only needed to do 1 or 2 takes to get it right, because he knew how to treat kids.

Your character is becoming as popular as Father Christmas. How does that make you feel?

No pressure then?! I guess Ill have to put an end to pictures of me falling out of nightclubs drunk.