Bad Education star Charlie Wernham is returning to Abbey Grove after almost ten years - but this time as a teacher, with a fresh set of rowdy students making up the new Class K.
Mitchell's student-to-teacher transformation isn't the only notable difference from the old series, however. Sitting down with HELLO!, Charlie revealed how the show's humour "had to change" to align with the evolution of comedy over the past decade - while also discussing how the new season came about and his hopes for series five.
WATCH: Charlie Wernham and Jack Whitehall star in the reunion special
It's been over ten years since the first series aired. How did it feel to return with season four?
It was very daunting, actually. I was quite nervous. I wasn't nervous until day one [of filming]. I was really excited at the prospect of it coming back and then we did a lot in the writers' room, with myself and Layton [Williams] part of the creative team.
That was all fun and exciting but then on day one I was really nervous because I was like, 'Oh god, I'm doing it again'. It was scary because people loved it so much. I always forget how much people enjoyed it and then the responsibility started coming back to me again. We've got to make it as good as it can be otherwise people won't enjoy it. So it was daunting but very exciting.
Exclusive: Silent Witness stars Emilia Fox and David Caves reveal all on Nikki and Jack's romance
Exclusive: Iwan Rheon on how Light in the Hall's Joe is a different kind of villain to Game of Thrones' Ramsay
How did the idea for a new series come about?
I was in Costco in January last year and Jack [Whitehall] called me and said, 'Look, we're thinking of doing a special reunion episode because it's been 10 years' and I went, 'Are you kidding me? Has it actually been ten years?'
He said, 'We want to do this special with the BBC and get the old gang back and get Alfie [Jack's character] back in there. Are you up for it?' And obviously, I was like, 'Yeah, of course.'
Then he added that they were looking at possibly doing a spin-off series off the back of the reunion, which would introduce a new Class K and say goodbye to Alfie and the old gang with Layton and I heading the series.
A few months later, we were given the green light and were in the writers' room creating it. It was a very quick turnaround but completely out of the blue because I didn't honestly think we'd ever be doing a Bad Education again.
What was it like filming in a real school? Did you have children trying to interrupt filming?
A lot of the kids were used to it. Apparently, there's quite a bit of filming at this school, so they were really good but what was really funny was Layton and I were saying, 'Oh god, this is the demographic for Bad Ed, so people are going to recognise us and the old class and Jack and Mat [Horne]. It's gonna be a bit carnage because it's a small show set.
It made us feel really old because not one of them knew who we were. I realised that when the series came out, most of these kids were between three and nine. I felt very old.
Check out HELLO!'s ultimate 2023 TV special
What can you tell us about Mitchell? Where is he at in his life?
You see him trying really hard to do the right thing in keeping his teaching job, which he gets in the reunion. He snaps it up because he knows it's a good opportunity to get a stable income and look after his newborn child he's got with his girlfriend.
Layton Williams and Charlie Wernham as Stephen and Mitchell
He's got a lot of responsibilities and his heart's in the right place, but Mitchell being Mitchell, he's tried to do a lot of growing up but hasn't quite achieved it. So he's still making mistakes, he's still putting his foot in it, he's still running scams and saying the wrong thing.
But like we see him in the old series, it's all out of love and there's no malice in him. He's just a bit of an idiot and it gets him into a lot of trouble.
It's been ten years since the first episode and comedy has changed so much in that time. Do you think the humour is different in the new series?
Definitely. It had to be. Things move quickly in society, and quite rightly so. There are a lot of things that we said ten years ago or did ten years ago where it's not the right thing to do nowadays. So we had to change our comedy. The thing about Bad Ed is it had to develop, otherwise it just wasn't right.
So that's what the team of writers have done really well but they also didn't lose the pace. Bad Ed has a lot of one-liners and bouncing off of each other and I think we've got that right.
We just had to be a bit more clever with where the jokes were coming from and I think we achieved that.
The series returns on 16 January
Do you have a favourite moment from filming?
My one favourite moment is there's an episode where two teachers that work in the school, they are husband and wife, have an argument in the canteen. It's the old classic of throwing drinks over someone.
We went for a rehearsal right near the end of the day and they go, 'Okay, guys this is a rehearsal. Don't actually throw anything.'
We were watching it and this lady threw all of the drinks and food over this guy and the camera wasn't even rolling and he wasn't in his costume yet. His own clothes got absolutely covered in spaghetti bolognese and Diet Coke and he just took it. It was a disaster at the time because it set us back by about an hour, but looking back it's hilarious.
Will there be another season?
I know everyone that worked on it would love to: the cast, crew and writers. We absolutely enjoyed every minute of it. It's just a case of if people enjoy it, if the BBC are happy with it and if people want it. If people want it then let's see.
I enjoyed it so much that I would jump at the chance to do it again. The new actors and actresses that have come into the show for Class K are so talented and have so much to offer, so I think it would be great to explore them a bit more. I've got my fingers crossed anyway.
Bad Education series four is available to stream on BBC iPlayer from 16 January.
Like this story? Sign up to our What to Watch newsletter to get other stories like this delivered straight to your inbox.