David Walliams was so impressed by precocious stand-up comedian Jack Carroll‘s performance on Britain’s Got Talent that he asked him to play a guest role in his secondary school sitcom Big School.

Jack, 15, whose comedy act includes material about living with cerebral palsy, appears in this week’s episode as a new arrival at Greybridge school.

Wheelchair-bound Dean has no problems dealing with his disability, yet he is earmarked by inept French teacher Miss Postern (Catherine Tate) as an ideal vehicle for flagging up her latest school initiative, an anti-bullying campaign.

“I’ve stayed in touch with Jack and his mum ever since Britain’s Got Talent and I am delighted that he wanted to be part of the series,” says Big School co-creator David, who plays lovelorn Deputy Head of science Keith Church in the series. “He was perfect to play a kid in this series and really funny.”

We caught up with Jack for a quick half-term report…

Jack, you seem a real natural when it comes to acting. How much experience have you had?

“I don’t remember things very well – my mum will tell you. I was in Ministry of Curious Stuff, the CBBC series with Vic Reeves.”

And you’re now working with another comedy legend, David Walliams…

“Yes, off the old BGT. He’s been really good to me and it’s nice to have people in the industry who are like that.”

What has your own experience of big school been like?

“I don’t enjoy school very much. I don’t like sitting in a classroom. That very formal environment doesn’t suit me. So in Big School I went all method and acted bored.”

Did you take any exams this summer?

“I’ve taken my English GCSE a year early and passed it which is good – against all odds. I got a C.”

Were you a fan of David Walliams in Little Britain before you appeared on Britain’s Got Talent?

“That was the first comedy programme I watched. My brother and my cousin were baby sitting; and they let me watch it but they said you mustn’t repeat anything you hear on it.”

How would David do as a contestant on BGT rather than a judge?

“I’d put him through to the final – I think everyone in the nation would.”

Are there any similarities between your school and the one in Big School?

“No. One of them’s real and the other one’s on the TV.”

How about the teachers – are they similar?

“My teachers are demons from another planet. They must come from a specific race.”

What other work do you have coming up?

“I’m appearing in supermarket sitcom Trollied as Harry, who works on the checkouts at weekends. It must be perpetually Saturday on that show because I’m in eight episodes. That was the first massive thing that I’ve done that’s a sitcom.”

Who’s your favourite stand-up?

“I went to see Stewart Lee in February – that was great. But I hate being asked this question. If you come and look in my bedroom, I have a big wall of  comedy DVDs. To pick any favourite out of them would be doing a disservice to everyone.”

Jack can be seen in Big School on Friday October 3 at 9.30pm on BBC1.