The wait for series two of Doctor Who is almost over with the first episode ready to be shown on Saturday 15 April.
Just before it went out Newsround nipped down to Wales to quiz the stars of the show to see if they'd spill any secrets.
So what did Billie Piper, who plays Rose Tyler (which of course you knew already!), have to say about getting to know a new Doctor...
Second series, how's it all going?
Everything is going really well. It's been a nine-month shoot, but it's gone really quickly this year and I'm a bit sad about that really.
But I'm quite looking forward to going back to London, to see my friends and family.
It's been awesome, it's been great. We've had a whole host of different characters this year. We've had werewolves, cyberman and cat-nun-nurses.
Loads of new things, it's a very exciting show.
What's the really scary thing that's going to frighten kids the most?
I think the Satan Pit is quite terrifying because it deals with the devil and that's something we're all kind of aware of from the moment we start reading and learning, depending on what your religious stance is on stuff.
You just know about the devil, you know about heaven and hell and so it's something that's quite spooky and scary. I frankly think that's the scariest.
But the kids may like the Cybermen! I never know what the kids like and what's going to scare them more.
What's it like working with the new Doctor Who, David Tennant?
Working with David is a delight. He's a top bloke, he's lovely, he's really cool, very down to Earth. Very generous in spirit, he's great, he's just perfect.
In this series you meet a past companion of the Doctor, and stuff between you is quite sparky, what was that like?
Yeah, Sarah Jane (Smith) and I, we have a great catfight.
The thing is about Rose this time around is that she's more tetchy and more possessive over the Doctor because she feels like she's lost him once and doesn't want to lose him again. And she understands that he can be taken away from her like that.
This time around she's a bit edgy, so when she meets Sarah Jane it's a bit like meeting the ex-girlfriend, which doesn't go down well.
So, are you going to be back for series three?
I'm not telling anyone because episode 13 is so brilliant, it's just worth waiting for.
Bearing in mind it's science fiction and anything can happen - I think it's something you're just going to have to wait and see.
There are all sorts of rumours though...
Rumours are endless, but they were saying that stuff this time last year about me leaving, about us all leaving. It's just worth waiting for I think.
You've said that climax to this series is amazing, but how can you top last series' end? You were a time goddess!
I thought the same thing: "How can you top those last two scripts from series one?" But the genius (writer Russell T Davies) has done it again.