Waking the Dead’s Wil Johnson is Waterloo Road’s new geography teacher, Marcus Kirby – but his first day doesn’t go well…

What can you tell us about Marcus? What kind of person is he?
“I’d describe him as a fiercely committed father to his two children, Jonah and Ruth. He loves them more than anything else and has sacrificed everything for them – even his career. He was a university lecturer and did very well, but when he became disillusioned with the state school system, he pulled them out and home-tutored them for five years. They’re very bright, especially his daughter – she’s a prodigy. He put them back in school because his ex-wife thought they needed social contact. He’s reluctantly agreed, but takes a post at the school so he can monitor their education.”

He gets involved in the case of Ronan, who seems to be troubled this week?
“Yeah, he catches Ronan selling DVDs and feels the need to reach out and help him. He has no idea that Ronan’s dad – played by Martin Kemp – is from a shady, criminal world, the opposite end of the scale for Marcus, who’s the epitome of an upstanding citizen.”

Don’t you end up having a punch-up with Martin Kemp?!
“Yes, it was fun! It was an absolute joy working with Martin – what a gentleman, such a nice guy and we had such a great rapport. When we had to get down, we got down – when it was time to chill and relax, it was really Kool and the Gang!”

Any injuries?
“Not for me. Martin had a slipped disc when we were filming and he was in a lot of pain filming the fight! I was fine – I’m a geezer!”

What were you like at school?
“I was the kid who was not afraid to speak his mind – and that got me in trouble a few times, even if I was right, as you weren’t supposed to speak to a teacher that way. I was a bit of a cheeky kid as I wasn’t afraid to stand out from the crowd. Some teachers admired it and some said, ‘You’ll get nowhere, Johnson, with that attitude!’”

Did you get into drama at school?
“Only in my final year, it was a bit of a fluke really. Funnily enough, drama had been the subject I hated most so when we came to our options, I opted out. It was all about football, girls and raving and going out and getting a proper job. I thought drama was nonsense – sex, drugs, rock and roll and all that. And in my neighbourhood, being an actor wasn’t a cool thing.

“Going on stage and doing Shakespeare – what was that?! That was not the done thing! But my drama teacher kept saying I’d be good at it. I was like, please, why would I want to be an actor? So fast forward to my final year, the lead drops out of the school play and the drama teacher asks me, of all people, to step into the role. I then found out the girl I really liked was in it and I’d play her boyfriend, and even get to kiss her. So I said, ‘I’ll do it!’ That was my motive – to get to this girl! In the process I caught the acting bug and haven’t looked back since.”

Would you make a good teacher?
“I think I would. I take my yardstick for that from being a father and helping them. I’m very fair but firm at the same time. I help with homework and read to them and try to teach them about life, more from a spiritual point of view. I’m not so much a bookworm. I’m viewed more like a philosopher! My children range from four and a half to 25. They’re made up I’m in Waterloo Road. And all my nephews and nieces think I’m so cool now. I had no idea how popular the show was until I got it and told them. They were like, ‘Oh my God!’ I was like, ‘Breathe, breathe into a paper bag. Don’t hyperventilate!’ I’m very popular at the moment!”

Are you going to be doing any more Waking The Dead?
“We’re filming another series now. It’s fun going back as such a different character from Marcus in Waterloo Road – it’s interesting going from being one of the eldest and then going back to Waking The Dead with Trevor Eve and Sue Johnston and feeling a junior again because of our age differences.”

What would be your ideal role?
“I’d love to do an action sci-fi thriller. Something like The Matrix. I’d like to play the one that saves the day! I go to the gym and have been for years, and I want to get my shirt off now. Come on! I’m 45. I’ve still got the six pack and want to show it off while I have it!”

Can you tell us what’s coming for Marcus?
“Juicy twists and turns! I can’t say what…”

*Waterloo Road is on Wednesday at 8pm on BBC1