Emma Watson plays Hermione Granger in Harry Potter and the Goblet of Fire.
Newsround chatted with her to find out the gossip from behind the scenes...
You can also watch our interview with Emma in full by clicking on the Newsround Player link on the right and selecting Potter.
This was a very different film to make, it's much more intense and dark, how was that to work on?
It was nice actually, I think every film probably gets a bit darker, a bit scarier and evolves. I liked the challenge, it was really good.
And of course one of the big challenges on this film was learning to dance. What was that like?
Waltzing is unlike any other dance, it's actually really difficult. I was surprised at how hard I found it. But hopefully it pays off and it looks good in the films.
Did you have weeks and weeks of lessons to get you to get you up to Strictly Come Dancing standard?
I'm not quite that good yet, but we had quite few practices together and it was really good fun because all the cast was involved in that, which was nice.
We've had hints about Ron and Hermione in the past, and this time Viktor comes along, what was that like?
I thought the introduction of romance in what is a much darker film and this kind of awkwardness between boys and girls makes up for quite a lot of of the humour. I think it's great.
And what was Stanislav like?
He was a really nice guy, genuinely a really, really nice guy. We had a lot of fun learning to dance, it was great.
The hints about Ron and Hemione are still going on, How do you feel about that, are you looking forward to that, or do you wish JK hadn't gone there?
No, no, I'm completely the opposite. I just want them to get on with it really. They're so different, but they're so perfect. He loves her and she likes him. It's just been going on too long, they've got to get it together.
So when you read the sixth book were you thinking come on?
Yeah that was exactly it. The whole thing is just about them making each other jealous, they've got to get it together. Definitely.
In this film we see a lot other changes too. Harry and Ron fall out dreadfully. What was it like having to referee all that?
I loved it, I loved all the arguing, it makes it much more real. I mean they've been friends for four years and not really had an argument. I think it's more real and it's good to get your teeth into, arguing is great, I love it.
In this film you have my absolute favourite moment, at the ball, at the end people are just sweeping off and you give this amazing excited giggle, now that is a Bafta!
I think she's really nervous, I think she's really, really nervous and I don't think she's quite sure how she looks.
It's early days now, there are three films to go, but do you think it's possible you'll do all seven films?
Every film takes like a year to do and the six months after that is all the production so you kind of have to take it one film at a time because otherwise it's a bit overwhelming, but I can tell you that I'm back in February for the fifth film. I'm on for the fifth, I know that much.
Are you looking forward to that? Because Hermione is sort of Harry's compass in that film because Harry is going off the edge a bit...
Yeah, I think she always is the girl who sort of grounds him, and she really, really looks out for him. She's a bit of a mother figure I think now.
What are your favourite moments in this particular film to make? Because you get to do a lot of fun stuff...
It's difficult to say. I did really enjoy the Yule Ball scene just because we had all the cast involved and it was just a really exciting scene. Everyone got really dressed up and it all looked beautiful, it's great.