The Sarah Jane Adventures star has been cast as pupil Kevin Skelton, who initially seems to be a troublemaker thanks to some mischievous behaviour in lessons. However, Chalky soon suspects that the new boy could be more intelligent than he's letting on…
Digital Spy recently caught up with Tommy to hear what fans can expect from Kevin's arrival and the character's future.
How well have you settled into Waterloo Road?
"Settling in was quite easy, actually, as everyone was very welcoming. It sounds like a cliché, but it is a nice little family here - all of us are really good mates and everyone gets on well. I was welcomed very nicely!"
Were you nervous at first, though?
"I was definitely nervous on my first day, which was a few months ago now as it was mid-May when I started. I hadn't been on a set for quite a while so I had to get back into the swing of things, but after day one I knew that I was going to enjoy this. It was good fun from then on."
How did the part come about?
"Well, I actually auditioned for the part of Drew, who was in episode one of the current series. That was the script that I read in my audition, but after that I was offered the part of Kevin, which I guess is a bit of an upgrade because he's a regular.
"So in my audition scenes I was doing a lot of shouting and screaming asking, 'Where's my girlfriend?', and then I got offered this part of a nerdy kid, which is just as good - even better, I think!"
How would you describe the character of Kevin?
"Kevin is a foster child, who's been through many families and been to many different schools. He's constantly moving about all over the place, and it seems that he's been let down a bit in his past, so his expectations when it comes to things are incredibly low. He doesn't really expect much out of life.
"At the same time, Kevin is incredibly intelligent, but he's almost shy or ashamed of it, as if he's been bullied in the past. So he hides that away to start off with - it's not something that he's proud of, so he doesn't answer any of the questions in lessons. He also winds up the teachers and stuff like that. But later on, you find out he's a bit of an intelligent chap."
Does he show his true self to any of the other characters as the episodes progress?
"Yeah, he does eventually come out of his shell. He forms a nice little relationship with Chalky, because they've both got this mutual fondness for maths and science. That's when he shows how brilliant he is academically."
Some of your first scenes are with a troubled student named Morag, aren't they?
"They are, and these are some of the scenes that I really enjoyed doing, because it kind of shows the nice, gentle side to Kevin. You see in some scenes that he's winding up the teachers, but then he's walking along the corridor and poor little Morag's standing there verging on tears after a really difficult day.
"But Kevin advises Morag not to let other people get to her and cheers her up. At that point, the viewers will see that although he has a certain attitude in lessons, it's not the person he really is because you see him having this real gentle side to a girl who needs his help."
How have you found working with Mark Benton, who plays Chalky?
"Oh, the guy is phenomenal. Some of the scenes that we did literally blew me away. He's the funniest guy I've ever met and it's never a dull scene if he's in it. I'm just a bit gutted he's not here anymore."
Do we find out much about Kevin's background and why he's in foster care?
"It's something that we haven't really touched upon yet. I think most of that is up to my interpretation, I guess. It's slightly spoken about, but we've never really gone into much detail. Maybe we will in the future."
Is it true that Kevin becomes good friends with Connor?
"Yeah, those two form quite a nice little friendship together. To start off with, Kevin is showing off in front of Connor quite a bit, because he wants to prove himself. But in the end there's a great, genuine friendship that those two have together. They become best mates, which is nice."
Will Kevin become involved in Connor's dramas with his alcoholic mum Christine?
"Not early on in the series - he's more of a social mate at school. But later on down the line, he does become quite involved in Connor's personal life. He becomes like a pillar for him and he helps Connor out as quite a strong sidekick."
Does Kevin become a popular figure at the school?
"Yeah, he doesn't really have any enemies as far as I'm aware. Obviously there are a few bullies in the school who lay into everybody, but he doesn't seem to have any bad blood with anybody. He's a likeable character and hopefully people will see that."
Which cast members have you made friends with in real life?
"Literally every single one of these people is incredible. We all live on the same road in Greenock, so we're constantly going round to each other's houses and playing Xbox and things like that.
"Shane O'Meara, who plays Connor, was one of the first people to properly take me under his wing. He showed me about the place and really welcomed me. I appreciated that - he's a nice guy, so we've become good friends."
Are you looking forward to being known for a completely different role now?
"Well, the attention side of acting isn't really my favourite thing, I'll be honest! I was out in Glasgow high street a few weeks ago and I was with Kaya Moore who plays Phoenix, and with the amount of attention he was getting, it must have taken us a couple of hours to get down the high street!
"I was standing there thinking, 'Oh my word', and I was a little bit worried about it. It's a bit intimidating as being on Waterloo Road will probably mean the most attention I've ever had. I think I'll be alright, I suppose I'll just have to see how I feel about it when it happens."
Do you get recognised much already?
"It's toned down a lot recently. When Sarah Jane was first out, I was recognised an awful lot. I used to pick up my little brother from his primary school every day and I remember when the show first aired, it got really hectic around the primary school. I was trying to find my little brother among all these kids going, 'Sign my contacts book!' and 'Sign my face!'"
How does Waterloo Road compare to the work you've done in the past?
"There's a lot more cast members, which means the amount of time I work is slightly less. I'll have maybe a day off every week which is quite nice - it makes it a lot easier because I'm not in as heavily as I have been before.
"I also think the set is incredible - how the whole production, the behind-the-scenes stuff and the school is all in the one building. On my first day, I was just roaming about the place, going in every door and getting to know my way around!"
Will you watch your first episode when it goes out?
"No, I won't! I don't really like watching myself - I can't enjoy the programme when I'm in it. I've watched all of the episodes leading up to this next one, but I think now I'm going to call it quits!"
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Waterloo Road airs Thursdays at 8pm on BBC One. Get the Inside Soap magazine on your iPhone or iPad