Jessica Atkins, 11, played a young French girl called Reinette in recent Doctor Who episode The Girl In The Fireplace.
Here she tells Newsround what it was meeting the stars and filming on the famous set.
Are you a Doctor Who fan?
Yes, I'm a really big Doctor Who fan. It's a good programme because sometimes on TV you can predict what's going to happen after every take, but Doctor Who draws you in - you forget how it's being filmed.
When you compare it to the old series from my mum's time it's much better now. I watched all of last year's series - and this so far.
It was quite a complicated episode - did you understand the plot?
I did - once I watched it. Reading the script you still don't understand it as it looks a bit confusing. But when you watch it, it becomes clearer.
Did it take you long to learn your lines?
Not that long - I don't find learning words hard. Me and my mum just practise sitting on the bed reading the lines. Then she held the script and read the other characters and I would say my lines.
Have you been acting for long?
I started when I was about eight. I just like the fact that you can be anyone you want to be and you can just really feel what other people feel.
When you pretend and put yourself into their shoes you know exactly what they're feeling.
What was it like being on set? Did you get to go into the TARDIS?
I was just really gobsmacked. You saw bits and bobs from the first series - I saw The Face of Boe and a Dalek without a head which was quite scary. My mum saw it and because she remembered it from when she was a kid she shivered and thought it was really spooky.
I saw the TARDIS - I saw the set from the inside. I also saw the actual TARDIS police box.
Did you get a chance to chat to the stars?
I chatted with Noel Clarke who plays Mickey, Rose's boyfriend, and David Tennant who plays the Doctor. Noel was really lovely. He was the first star I saw - and he was really friendly and made me feel less nervous. David was as lovely as Noel and in-between takes he'd come and chat to me and ask me lots of questions. I got to find out about people and he got to find out about me.
Where you disappointed you didn't have to speak in a French accent?
I was actually quite glad. I was a bit disappointed I couldn't attempt it but then realised I would not be able to do it if I tried.
What acting have you done before?
I've filmed a DVD about teaching Spanish people to learn English. I've also done school shows and dance school shows. Most recently I played Lucy in a school production of The Lion, The Witch And the Wardrobe.
Since the episode went out have you had much reaction from people?
No one has really recognised me but all my friends said 'Wow, you were fantastic!' The phone has not stopped ringing and my mum's mobile kept on bleeping with texts saying it was lovely and they enjoyed it. I was really touched by some of the messages.
Some of my friends thought that it wasn't my real hair because I always wear it up for school - no one could believe how long it is.
Do you want to be an actor after you leave school?
I really want to be an actor now. Doing Doctor Who made me think that's what I want to do. I want to hopefully go away to an acting or drama school and maybe do a bit of singing and dancing - I like that too. But I really like acting and I'd like to do musicals.