You play being heartbroken very well. It was so evident in your face.
She just feels so embarrassed, and very exposed at that moment, very raw. At that age, you become soooo heartbroken by boys, you develop such big crushes, and then you're soooo devastated when they don't work out. I really do feel her pain.

Do you remember this chapter of your own life?
Yes. It's always going to be incredibly hurtful when your love is unrequited. And there's an age where you remember things so vividly. I think that's why J. K. Rowling writes so brilliantly. She must have had these experiences, because otherwise she wouldn't have been able to write them so pitch-perfectly. It's great, because she really does transport everybody back to that period in their life. This book especially is so, so accurate of teenage obsession and hormones raging.

And the crowds staring at you?
I actually couldn't really see anything. I didn't have my contacts in, because I'd forgotten them, so I was quite happy in my own little world.

And the next film?
I am doing Harry Potter 8, so I'm doing the final section of the books where I'm in battle and Lavender kind of gets almost killed, or she dies, which I definitely know I'm going to be back for!