Win £250 to spend on a designer wardrobe at Secretsales.com. Click here to enter now

Do you feel like you're at the end of a journey?
I feel really pressured because I feel like this is my last go, my last shot. I don't want to have any regrets. I want it to be the best performance I've ever given. I want to know that I've done the best that I can possibly do. It's really strange.

When did you find time to study?
It's something I really wanted for myself. If you want something enough, you make time to do it. I'd do most of my reading when I was sat in the make-up truck. I'd sit and write and I'd have my laptop on my lap and I worked weekends. It was exhausting. But it's so worth it, I'm so proud.

What were the challenges involved in making "Half Blood Prince"?
There's a lot more to do with the relationship between Hermione and Ron. Hermione got very serious in the last couple of films so it was really nice to get to do some funny bits with Rupert and he's great at that. Hermione's the ones who does all the thinking and planning. Sometimes I look at her and think, I can't believe she doesn't just collapse ... You must be so bored of hearing us say, "They're getting darker," but it is going that way!

Do you have a favourite scene?
The Quidditch scene with Ron. I couldn't believe how funny it was, he just killed me. I couldn't stop laughing. Having said that, it was my favourite to film - it was one of the coldest days of the year and we were out there for hours!

How do you think you've changed over the course of the series?
I've changed a lot in some ways and not a lot in others. I've gone from the age of nine to 20, so that's 10 years. I guess I've become a lot more comfortable with filmmaking. It was all so new to me but now it's just second nature. It's got to the point where I am able to be much more creative with it. I know the character like the back of my hand.

Do you always keep the "Harry Potter" books close at hand?
Yeah, I love [Rowling]'s work. I've always loved the books. I'm the first person to say, "This is not as good as it's written in the book." I'll be the one saying, "This line's much better, it's in the book!"

Do you have a favourite?
I love the third one. I just remember my dad reading it to me and I loved it. It's also my favourite film and it was a great part for Hermione. I had a part that I could really get my teeth into. I like the tomboy aspect of Hermione, that she was part of the action.

What do you like about Hermione?
She's got a heard of gold. She's the first person to sympathise with anyone in opposition to her. She's so determined, loyal and she's such a strong girl ... woman! She's the ultimate girl.

How have you coped with being in the public eye?
I used to live in Oxford, but now I live in London so that I can be closer to the film sets. The commute was just crazy. Since moving to London I'm starting to feel that tension when I walk out of my door. "Harry Potter" has such a high level of interest, anything - even if it's nothing - is news.

Did you think it would be this big?
Even if producer David Heyman has known, how do you explain that to a nine year old? I was so naive. the first time someone asked me to sign a book I thought it was the weirded thing ever.

Which of the big famous actors have you bonded with the most?
I found that a lot of actors are involved in art - something I love and I did for A-Level. I ended up talking to Alan Rickman because he went to art school, so did Robbie Coltrane and Chris Columbus and Judi Dench. And I really got on with Emma Thompson. I also loved how she was so down to earth, so normal and so kind, and she doesn't ignore anyone and pays attention to everyone from the sound guy to the director. I really loved her to bits. Maggie [Smith] is an absolute sweetie. She sends me chocolates and a note at Christmas.

What about J.K. Rowling?
She has more input in the films now that she's stopped writing the books, but she's so busy. She's got a family and she's writing and everything. She's more involved now, which is really nice and whenever I see her I get on really well with her. She's really funny - very, very witty.

Is she much like Hermione?
Definitely. You can see it. She's so clever!