The new star of Doctor Who describes how his life – and his mum’s – has changed since he won the part of the iconic BBC One character…

How did you react when you found out you had the role? “Well, I couldn’t tell anyone for over two months, but I told my mum, dad and my sister. My then flatmate worked it out because I kept having secretive conversations with my agent and I would come back in the room and pace around. Obviously my heart was just exploding inside of me with joy and excitement and then I had to wait until it was announced and I was in Brazil then.”

What is your favourite thing about being the Doctor so far?

“That’s a tough one. The TARDIS or the sonic screwdriver maybe. What is so thrilling about it as an actor is that every day is unlike anything else.. It is such a thrill every morning, you never quite know how the day is going to go, but in terms of his world I think my favourite thing is his brain. I like being able to get into the head the cleverest man in the universe, which he is.”

How do you feel about being the youngest ever Doctor? “Well, I think the Doctor is the Doctor and he has been for 40-odd years, but if we are talking about his age, he is over 900 and is there any actor that age? I just think the body is a vessel for the man’s brilliant mind and two hearts and wonderful soul.”

What sort of Doctor is he?

“I think he is a bit of everything because he has been on so many adventures and he picks up so many things on the way. Every actor that plays him has a different soul and a personality and mind and therefore via my make-up and my body and my history he is my Doctor. I don’t think you can analyse anything artistic at the moment you are doing it. I try and play the truth every day and create the scene in the most inventive and brilliant way as I can.”

Did you get any advice from David Tennant?

“Not about the part, but I talked to David and Billie about being in the show and they are lovely souls. We just talked about life in Cardiff and life in this show, which was very helpful. We chatted about it as fans as much as anything else.”

Are you ready for the show’s hardcore fans?

“It is not something at this stage that I contemplate. Everyone is entitled to their opinion and it will still be the best part in the world. Of course I want them to enjoy the show because that is who it is for, this show is about the fans more than any other show, they are so integral to it and have been part of it for so many years. It is shared among so many generations, too, but I have been employed for my creativity and my interpretation so I just hold true to that. The fact that we have such obsessive fans though is part of what makes it so brilliant, but it’s for the mainstream as well and the fact it can be for both is part of what makes it magic.”

Is it a life-changing role?

“Yes, your daily life changes significantly, if you go into Tesco it is not quite the same as going into Tesco a year before. I am sure that will continue once it is on the telly, but it is just something you adapt to and like anything new in life, you change with as much grace as you can. My family are thrilled though; it changes their life too. My mum goes into work and she is Doctor Who’s mum. It is a mad thing!”

What makes it so popular?

“I think the character obviously, but I think it is just a brilliantly conceived format, it can go anywhere, do anything and breach any time, but at the heart of it you have these two people who are brilliant characters. Amy Pond is truly glorious. You are in for a real treat, I think she is one of the best companions ever.”

How would you describe their relationship?

“Well, I don’t want to give too much away, but she is a real challenge for the Doctor this time. She is feisty and witty and she gives him a run for his money. They meet in the most magical way. What I think Steven Moffat does so brilliantly is he taps into the fairytale, his mind is like a big magic fairytale and that really comes across in the script.”

What makes the ideal monster?

“I think they have got to thrill and frighten both the viewer and the Doctor. I think he is utterly intrigued by every monster but the Daleks are a different kettle of fish. That is such a great war, they are the one monster he would feel are inherently evil. We have got some great new monsters in this and some great old ones like the Weeping Angels.”

What state is the Doctor in when we meet him?

“Well he has just regenerated so he is going, ‘Who am I?’ He is figuring himself out, it is like a newborn baby, but over the age of 900 with the mind of a complete and utter genius. Due to the way he regenerates and what happens within the regeneration he has got a lot of get on with, so he is busy!”

*Doctor Who returns to BBC One on Saturday, April 3