Secrecy is everything in the iconic world of Doctor Who.

Cast changes are kept as quiet as possible until the big reveal. Codewords are used, actors don’t even know what they’re auditioning for, and not even the cast know where the storylines are going.

Doctor Who is the TV equivalent of MI5 – and into this world steps Birmingham actor Samuel Anderson as the show’s new ‘secret weapon’.

Not Peter Capaldi, the 12th Time Lord, but his new sidekick Sam.

Sam, who plays teacher Danny Pink in the hit sci-fi series, explains: “At the premiere for the new series, writer Steven Moffat referred to me as his secret weapon.

“It was the proudest moment of my life.”

Interviewing Sam, 32, is tricky as he has been told not to reveal anything about storylines and very little about his character.

He won’t even confirm when he first appears, although it’s a fair bet he will make his debut in episode two next week.

The series begins again on Saturday on BBC1 with an 80-minute special, Deep Breath, which will be simultaneously screened in some cinemas.

We do know that Danny will be the new boyfriend of Clara, played by Jenna Coleman.

He is a fellow teacher at Coal Hill School who knows nothing, at first, of her life as a time traveller. But when a new relief caretaker turns up with a Scottish accent, Clara’s two worlds collide.

Perhaps Sam is staying so tight-lipped because he has already been guilty of letting the cat out of the bag.

At least he wasn’t responsible for a major leak in July, when an unprotected ‘shared’ folder on the internet was infiltrated. Details of the first five scripts went public, much to the BBC’s horror.

“I had no idea Doctor Who was one of the most secretive shows on earth,” comments Sam.

“They didn’t tell me too much about the role when I auditioned. I thought it was just to appear in a couple of episodes, which was good actually because I didn’t feel under so much pressure.

“I thought it would cover me for the next month – but I ended up working on it for eight months and seven episodes.

“My agent rang to tell me I had got the part when I was with a group of friends. I came off the phone and told them ‘I’ve got Doctor Who!’

Dr Who stars Jenna Coleman and Peter Capaldi, meet fellow actor Samuel Anderson who will play Danny Pink.
Dr Who stars Jenna Coleman and Peter Capaldi, meet fellow actor Samuel Anderson who will play Danny Pink.
 

“Then my agent immediately rang back and said ‘By the way, don’t tell anyone’.

“Oops!

“When there was that big leak, I thought ‘Oh no, did I leave my script on the Tube?’. I was really worried it might be my fault.

“The cast are kept in the dark quite a lot. I got the script for one episode just the day before we filmed it and I had no idea where the character was going.

“As actors, we speculate just as much as the audience.”

Sam, an Aston Villa fan, found fame at the age of 22 in Alan Bennett’s play The History Boys. He was among the original National Theatre cast, alongside James Corden, Dominic Cooper and Russell Tovey, who toured the world then starred in the 2006 hit film.

In 2007, Sam joined the cast of Emmerdale as policeman Ross Kirk, a cousin of vet Paddy who had an affair with the late Donna Windsor before being wrongfully imprisoned for murder.

Sam was born in Handsworth and grew up in Perry Barr. He attended Stuart Bathurst RC High School in Wednesbury and his parents, Margaret and Samuel, live in Sandwell.

Margaret runs a nursery on All Saints Way in West Bromwich called Little People’s House, while Samuel is a retired engineer.

His dad is overjoyed at his son joining the cast as he is a major Doctor Who fan.

“The original series was coming to an end when I was a boy, but I remember it being on telly. It was a big Saturday night thing in our house because my dad was a massive fan.

“He’s still a fan although he said the recent doctors were a bit too young for him.

“He loves Peter Capaldi. The younger guys who played the Doctor did a great job, but there’s something about real experience. There’s a certain weight and way you carry yourself that you just can’t act.

“Peter is a brilliant Doctor Who. His wit and stoic approach is just...wow.”

Danny is a maths teacher, so how did Sam fare in the subject while a pupil at Stuart Bathurst?

“I wasn’t too bad, although fractions still baffle me. I think I got a B in my GCSE.

“Generally I just didn’t want to do the work, though I was OK at school in some classes, the ones where I wanted to please a teacher I liked.

“My favourite teacher was Mr Rees, the deputy head and RE teacher.

“I dropped out of my A levels after a year. I took the easiest subjects I could find – film studies, PE and general studies.

“After a year my headmaster told me I was doing cop-out subjects and I needed to do a proper A level as well.

“It would have meant me staying on for an extra year so I never went back. I did a part-time course at Birmingham Theatre School then went to drama school in London.”

Not that Sam has stopped learning. He is a man of hidden talents – he is trying his hand at writing, planning on taking Spanish lessons and has been teaching himself to play the trumpet. As we speak, he’s been rehearsing with a marching brass band who were performing at the Royal Festival Hall.

“I’ve been learning the trumpet for about three years, mainly teaching myself,” he says.

“It is very difficult and I’m very aware of how my neighbours must feel.

“My lips are in agony! I thought it would be easy because it only has three buttons!

“I also did a writing course with a playwright last year, and I’d like to have a go at that.

“Although after working with Steven Moffat, I think ‘Maybe I’ll just put my pen back in the drawer’. I can never hope to be half as good as him, he is a genius.”

* Doctor Who begins on Saturday on BBC1 at 7.50pm.