What’s it like being part of the 50th, one of the biggest years on the show?

It’s amazing being part of the 50th anniversary. I just remember getting an email asking if I’d play Queen Elizabeth I, which in itself I couldn’t believe because she’s so iconic, even in the history of Doctor Who. I’ve always wanted to be in Doctor Who and now to be in it and playing Queen Elizabeth I is absolutely fantastic, so exciting.

And what did you do when you first found out about the news?

When I first found out about the news I phoned my mum and my dad and obviously, told my husband and then I sat down and read the script, because I couldn’t wait to get my hands on it. I just couldn’t believe that they had sent it to me as it was like gold dust. There were all these rumours in the papers about what’s happening, and so and so is coming back and I just thought I’m actually going to know what happens. I’ve never done a job where you have to keep a secret before and it’s been really difficult, but also really exciting because you know and no one else does.

You’re playing royalty. Can we expect a Queen Elizabeth with a Welsh twang?

Well, it’s very funny being one of the most well-known Welsh people and having to stand up and say, ‘How dare you, I’m the Queen of England’. That did make me laugh, but no, I’m playing her with an English accent. But John Hurt said she actually wouldn’t have had a very English accent, because there were so many different influences.

What was it like working Matt, David, Billie and Jenna?

It was quite scary working with Matt, David, Billie and Jenna because they’re iconic and they’re these major characters that I’ve watched and are part of Doctor Who history. It’s really funny acting with them because you look at them and they’re almost like cartoon characters because you see them so much and you’ve watched them and you believe them. It’s just been fascinating and working with the two Doctors is brilliant because it’s the same character, but seeing how the two boys just play them completely differently and how they work off each other, it’s really funny. After reading the script and then hearing it all in the read-through, it just all came to life and I thought, ‘Wow this is going to be fantastic’.

There’s a little bit of romance between Queen Elizabeth and the Tenth Doctor. What was is it like filming those scenes?

Filming the romantic scenes were quite difficult because my first day was on top of a mountain in Neath. It was absolutely freezing, it was blowing a gale and David, the Tenth Doctor and I, are having a picnic. So I’m lying across him and he probably couldn’t breathe, because I’ve just got this massive costume on, and he’s feeding me grapes as I’m just desperately shivering. You’ve got to try and play it romantic and relaxed, when actually you’re freezing cold. I think our lips were turning blue and I stopped feeling my hands. The next day, because it had been so cold with the wind my hands were bright red and all blistered because they were so chapped. So everyone is probably jealous, thinking she gets to kiss the Tenth Doctor and it’s all romantic, but it’s not; my lips were numb and my hands were chapped.

Where will you be watching the episode?

I’m going to be watching the episode in my living room. My husband has been asking for ages if we can buy a 3D TV and I said no, but now after putting on the glasses myself, it’s fantastic so I’ve said we have to get a 3D TV. So we’ll be watching it in the living room with all of my family round and then I’ll probably go to the cinema and watch it as well.