It’s not often you get the chance to hit a pop star in the face without facing criminal proceedings. So when we heard that an ex-boy band member fancied a boxing session, we wasted no time digging out our gloves. Matt Willis, 32, shot to fame as the singer/bassist of Busted, the power-pop trio who sold five million records during the 2000s. After they split, he went on to be a TV presenter and actor – as well as eating kangaroo anus and crocodile penis in the sixth series of I’m A Celebrity… Get Me Out Of Here!, winning the show in the process.

Busted re-formed last year and are just about to embark on a sold-out tour to promote their new album – but we are slightly concerned about Willis: if we were best known for a song about a time-traveller telling us that our great-great-great-granddaughter was a hottie, we might think twice about walking into a gym full of people who like landing a few punches…

So when you’ve been on the telly quite a lot, do you find that people want to put it on you in the gym?

A little bit. The first time I went to a Thai boxing class a guy gave me quite a hard time. He beelined for me when we were partnering up for sparring and he fucking smacked me around.

But it didn’t make you want to quit?

It didn’t really. It was just one dickhead in one class. Every other experience I’ve had in martial arts has been nothing but positive, especially in the MMA and BJJ [Brazilian jiu jitsu] gyms. It’s just a friendly environment and everyone wants to learn.

Are you a lethal weapon yet?

Not quite! I’ve not being doing this long so I’m definitely a beginner. I’m always one of the worst at every class, but I find people are very tolerant of that. They don’t want beat you up – they want to encourage you and help you.

So what inspired you to learn to fight?

My flatmate suggested watching a UFC event. I thought, “This is the most incredible thing I’ve ever seen”. I found myself watching it more and more. I’d have my mates over and we’d have UFC nights. I’d cook supposedly healthy food, and sometimes we’d train beforehand.

But watching fights is a few steps removed from actually doing it…

Training came a bit later. There was a point when I’d put on loads of weight and I got really unhealthy. I looked awful and I decided I needed to take care of myself more. I wasn’t interested in the gym so fighting was a way of keeping fit.

Was there one specific moment when you decided you needed to get into shape?

I got married and I hated myself in the wedding pictures. I looked like a fat mess.

What steps did you take?

I’d had a problem with drink and drugs and I stopped all that. But I still looked bad a year later. Then I realised, “Oh it’s probably because I’m eating fried chicken and drinking things with loads of sugar in”.

So it was the food that made everything click?

Once I started taking care of nutrition, it all clicked. I’ve got a bad relationship with food. I’m very obsessive about it.

You’re an all-or-nothing type guy?

I’ve learnt that I’m not very good at moderation. It doesn’t work for me. Anything that can be taken too far, I’ll take too far. Sugar is the worst. If I have it, something triggers in my brain… the same as it does with any other mind-altering substance. Something happens to me and I become a monster with it – I can’t control myself. Which is ridiculous and I hate it! But it’s just something about me, which I’ve had to learn.

Does that mean you don’t have any guilty pleasures?

I do have a bit of dark chocolate every now and again. I’m wild, aren’t I?

After warming up and hitting the pads, it’s time for some sparring. We do a few rounds and we sensibly keep it light, although one or two sneaky shots do get through. On both sides.

Now that we’ve punched each other let’s get to the intense questions… You’ve been in EastEnders and on the West End stage. Do you feel pressure to take acting seriously because you’re famous for something else?

Massively. I want to be fully prepared. In fact that’s how I am with everything now. Nothing good ever comes from not being prepared. I’m playing a part where there are fight scenes soon and I’m supposed to look like I can mess people up.

Does that change how you prepare?

Absolutely. It’s in the little details. I do fight training for fitness and for fun. But that presents some problems. For instance, I found out my elbows flare, which is fine if you’re just keeping fit, but you’d never do that as a boxer. I just need to look skilled in fucking people up.

Have you ever thought about fighting for real?

I was reading about Mark Wahlberg when he did The Fighter. His trainer was saying he would quite happily put him in the ring with any pro boxer and he would do well.

Are you calling Mark Wahlberg out?

No! I just need to get a boxing part, then I can train like that. Did you see the training videos for Warrior?

The ones with our dual obsessions, MMA and Tom Hardy? You bet we did.

They went to fight camp for four weeks. How cool is that? I would love to go to fight camp. You’d have to be there for your job. Training is a massive inconvenience to anyone’s life. There isn’t a convenient time to go – I have to put that into my day, so that often means I get up at 5am or train when everyone else is having lunch. To do that for your job? “My job today is to train all day.” That’s what I want.

You’re still best known for Busted. Do you want to leave that behind?

No, not at all. I love Busted. We got back together in June 2015 and we hadn’t been a band for about 12 years. Without being too dramatic, this is what I’ve wanted to happen for the last six years. I’m stoked about it! We went away and recorded some really amazing music, which we’re all really creatively happy with.

Does it sound like your old music?

It’s a massive progression.

Would you know it was Busted?

Probably not musically, but you’d hear it lyrically because we’re still us.

Last question. Do you stand by your prediction in the song Year 3000 that by then we’ll live underwater?

Well, with the way the world is going, we were actually ahead of our time… We’re going to go down as prophets.

And with that MF heads off to book ourselves some swimming lessons, leaving Willis dreaming of days just spent learning to fight and – possibly – soggy triple-breasted women. Or kangaroo anuses.