Lucky Evanna Lynch won the part of Luna Lovegood in the Harry Potter films after beating thousands of girls at open auditions.
She chatted to Newsround's Lizo Mzimba.
You can watch the full interview with Evanna on the Newsround Broadband player
You're a big Harry Potter fan. How long have you wanted to play Luna?
Well since she came into the books you know, I loved her all of a sudden and I always wanted to be in the films but I didn't know who I wanted to be and then when she came in I wanted to be her.
How difficult was it persuading your parents to let you come down to the audition?
Well my mum didn't want me to go, she thought I didn't have a hope. And then I told my dad and he thought I should go because he knew I really wanted it, so he brought me.
What were the auditions like?
It was mad it was, all the people, and it was really fun though because everyone was really excited. It was good.
Did I get to interview you in the queue or get close to interviewing you?
No you interviewed a girl two places in front of me!
What happened inside the audition?
Lizo just missed bumping into Evanna at the Luna auditions!
About 200 girls went into a room and there were two casting agents and they asked you to say your name and where you came from and then they picked two or three out of that. And they sent you into a room and I was really nervous and kept dropping things and I was going the wrong way and everything. Then she gave us a script and you had to learn it.
It was nice there because we all talked and it calmed you down. Then you went into a room by yourself and you said the script with another lady and the girl kept asking me to say it again and then she called in Fiona Weir (the casting director) and then they told me that they wanted to see me again.
What happened the following week?
I got a call on the Monday and they said we want you to come for a screen test on the Friday. And they were saying things like the director is going to call you today and you'll be doing your scenes with Daniel Radcliffe. I was a bit freaked out by that because it all happened so quickly. I thought there'd be loads of auditions but it was really quick.
What was the screen test like and when did you find out you'd got the part?
The screen test I thought went OK and it was really fine because Daniel was really easy to be with because he's very good at acting so you just believe he's Harry and he talked to me a lot. And he was nice. Then I found out three days later so that was good because I couldn't have stood all the waiting. I got a call when I was in a shop and they just told me then and I was just shocked.
What was it like when you finally found out you had this dream part of playing Luna who you always wanted to play?
I was just stunned because it was such a big dream and you always wish it will happen but I couldn't believe that it did happen.
You had to keep it a big secret didn't you, how difficult was that?
It was fine. I was resigned to the fact that I couldn't tell anyone so I just blocked it out and pretended it wasn't happening. I didn't have to worry because before I was waiting for the call and I was nervous. But this time I knew I had the part and I could just forget about it for a few days.
What was it like on the day it was announced you had the part, how did your life change?
It was mad. I went into school and all of my year were at the windows and they were all waving when I came in. And then all these camera people starting coming into the school and all the other girls were outside waving and I stayed inside and they didn't notice me. I think they had dyed my hair at that point so it was different and I had to have security people.
What's filming been like so far?
It's really fun. I just really enjoy the filming part and everyone's really, really nice. And you don't get nervous when you are talking to everyone. Well the first few days I was nervous but then when you start talking to people it's fine.
How similar are you to Luna and why do you think people like her so much?
People like her because she's like a breath of fresh air. Because in the fifth book it gets so dark and Harry's always cross and then every time Luna comes in all the tension goes and she makes you laugh because she's so funny and really honest. I don't know how much I'm like her, there are some similarities but I'm more determined than her.
Do you ever look at the Harry Potter internet fan sites to see what people think of you?
Well not about me. At first when it was announced I did check but then I got kind of upset because, you know, there are some people who will love you and some people who won't, and it will never happen that everyone will agree, so you just have to try and do your best. I have to do what I think Luna will be, and if that pleases some people then that's good.
Are you looking forward to filming the fight scenes in the Ministry of Magic at the end of the film?
Yes very much. That's going to be exciting. I was watching them building the set and it looks really good.
What was it like meeting JK Rowling, your favourite author?
Well just meeting JK Rowling was amazing because she created all this world. And all the fans, we all get so obsessed with it and then you met the one person who made it all up. It was just so amazing. And I was just so amazed that that she wrote this book and all of the films have happened. She was really, really nice and she's really easy to talk to. I was telling her my theories about what will happen and she just nodded. But she kept it secret, I don't want her to tell me.
Are you a really big Potter fan then?
I'm a huge fan. So it's not just like I wanted to be in a film. I wanted THIS part. I love the books - they make me feel happy. And it's something to do as well because of all the fans sites you can talk to people about it. The books are about magic so you can escape all the world here, and also they're about teenagers. They're normal teenagers, but they're magic, so you can still relate to them.
Tell me about your room and your pets
I redecorated my room recently. It's orange and I put my favourite quotes from the books in turquoise. I have loads of posters but they're too black so they make the room look really dark.
My cats - I have Luna who's just had kittens recently and we called one of them Dumbledore. They're nice but they're not like their characters. I had a cat called Crookshanks but he died.