Tom Rosenthal reveals that filming sex scenes isn't as exciting as you might think, and explains how his character Marcus now has a girlfriend.

Is it good to be back for another series of Plebs?

Good? It's excellent to be back with the gang. We know each other very well now; I always say it's quite nice that we've worked together for this amount of time and don't seem to hate each other. I think that's an achievement because each shoot is six to eight weeks, and that's a long time to spend with anybody, really.

We do seem to be friends, and we do seem to actually hang out when we're not wearing togas as well, back home, so I always count that as an achievement.

In between series you all go off and do other things, does that create a bit of competition between you?

It's like a friendly competition! It's like... 'oh, well done Joel, you've gone off to do a little show, pretending to be a serious man in a made-up country with an unpronounceable name, bravo... but, you know, me and Ryan have made our own TV shows, so... you know, two fingers up to you!'

You can't be a diva when you've just been filming a scene where you've been stark bollock naked, attacking a guard or had some sort of terrible sexual misadventure. I do think that the whole tone of the show, and the reason the show resonates to a certain extent, is that we don't take ourselves too seriously at all. I think the worst mistake you can make if you're trying to make a comedy is to be too worried about how you will be perceived. We are happy to make complete idiots of ourselves really.

Why do you think the show has become such a success?

Well, being inside it, I would say it's the amount of work and diligence and care the creators take over it. Sam, who writes and directs it, he is on top of absolutely everything that happens with Plebs, he sort of lives and breathes Plebs.

His brother is the producer, he obviously supports his brother's vision in any way he can, and Tom, the co-writer, is an extremely hard worker, they both work far too hard for a human being, and when you put that much care and attention into something, it's unlikely that it's going to be totally shit. And they very rarely drop the ball, they work really hard to make sure they get the best people, and it's also ambitious, it doesn't look like other comedy shows, you know?

It's basically about guys finding their way...

Basically, yes. We're just trying to make some money and get with girls or whatever and try and find a better deal, you know.

What do you make of the filthy jokes?

Er, my grandparents have to watch it with the sound off, or not at all! I mean, I was absolutely fine, but my parents have come to both screenings of the series and were generally "Yay!" or similar. But there was the scene where I had to perform oral sex on a girl, and I saw my sort of sinewy back with this kind of lizard-like approach, and my neck's all tense and I'm like, 'No one should ever have to see themselves doing that, especially with their parents.' People shouldn't have to go through that experience, that is the price of being in a low, bawdy comedy!

Are any of the gags off-limits?

Obviously being based in Ancient Rome, you can get away with a lot more. There's a way higher ratio of deaths in Plebs than there is in Benidorm for example, a lot more amputations, lot more sort of weird stuff to animals.

How do you feel doing sex scenes?

I know that everyone says this, but they're not as exciting as you'd think. They're a bit weird because you're surrounded by 25 Bulgarian guys with heavy machinery who are filming you manufacturing this sexual encounter. Generally I'm just worried about getting my arm in the right place and that the camera can see my stupid, funny face.

I apologise to any girl who has to have a sex scene with me, because I'm sure it's deeply unpleasant experience. But for me I sort of switch off and I don't see it as a sexual encounter because I'm just worried about it being funny really, do you know what I mean? You break people down into being props, rather than actors.

It's the least sensitive thing ever, and obviously you can't really brag about it to your mates and go, "I got off with this girl," because it doesn't really count. Know what I mean? There's nothing to benefit from, and as I say it's probably much worse for them than it is for me.

We hear you get to 'motorboat' Maureen Lipman!

Wow, it's sort of not really in the script that, as such, that I motorboat her. There's an earthquake and I sort of bounce into her quaking breast pillows. That is essentially the point. And it was wonderful! I can't complain. I mean, she's not only a woman of great comic talents, but also physically, you know... welcoming! She was like, "It's fine, don't worry - go for it." I was like, "Are you sure? Can I put my hands here?" She was like, "Go for it." So for about two minutes I had my hands and face on both boobs.

Marcus has a girlfriend this series, doesn't he?

He has. Well, he starts off the series moaning about his lack of options, then this girl grabs him in the street and sort of implores him to pretend to be her boyfriend because she's being chased by the police. That's a good guide as to what kind of character she is; she's quite alternative, she's Gaelic, you know, French, and she's very much a liberal protestor. She's all about animal rights, so when people are getting thrown to the lions she's complaining, protesting for the lions rather than the people.

Marcus, because he's besotted with this French princess, basically goes along with it and he has to pretend that he's into the whole liberal vibe, when actually he's almost the opposite. She's exciting, she wants to have sex in graveyards and stuff, and Marcus finds that a bit disrespectful, and she wants to go and have threesomes with her friends but Marcus is a bit disgusted by all her friends!

So she's a sexual person?

I guess she is, and I guess Marcus is sexual, but in kind of a direct, lights off, covers up kind of way. Whereas she's very much there naked all the time and loving the danger of it all.

And he gets mugged this series too...

He does a bit, yes. This thug comes up to the lads but because they're plebs they don't really have anything good, but Delphine's got this nice necklace, so he's like, "Give him the necklace, he's going to stab us!" He's not chivalrous, he's shrivelly.

Do the local extras get the humour on set?

They get the penis statues, they love all that. Basically anything Grumio does, because Grumio is very much sort of like, putting stuff on his head, snapping his dick off kind of thing, which anyone can get. Whereas jokes that are based on wordplay seem to go over their head.

Is there any you in Marcus?

Yes, quite a lot! They do certainly write them for me, but I would like to think that I'm better with girls than Marcus is, that I wouldn't just give my girlfriend's necklace away if someone tried to mug us. I don't know if I'd get naked at a protest, to be fair. Probably not!

It is quite a difficult question to answer, but I suppose I am. I complain a lot in real life, I've got quite a nasal voice and I'm probably quite annoying to be around, I'm quite a negative individual.

Your dad [Jim Rosenthal] has been in the show before, any chance he will pop up again?

He's annoyingly been working this whole time but he keeps ringing me trying to get back in it. I'm like his agent now, I take a bit of a commission. Got to get my mum in it. My girlfriend is actually coming out, I've got to try and get her and her brother in it and stuff - I'm like a casting director by now, it's exciting.

Any funny moments or mishaps on set?

There always is! The part where I'm getting arrested by the centurions, at the same time Grumio has already stripped off for the naked protest. He attacks a centurion whilst completely naked essentially, so whether you would describe it as a mishap or not, Ryan has to jump on the centurion's back and he was worried that he was exposing the innards of his bum. So the director had to come in and check that wasn't happening, and we're like, "This is work! This is a day at work!" Literally like a nightmare. All the Bulgarians freezing, covered in tomatoes... it's like some sort of medieval painting or something, it was horrific!

An average day in Plebs...

It really was! It's so weird. But most days do throw up something pretty bloody peculiar, you sort of get used to it. 'Here you go, the props list for today's shoot... face mask, paddle, strap-on'... that's happening, that's just today!

Are the other guys anything like their characters?

I guess when Joel gets really drunk on a night out and he's dancing around to music, he's got a bit of Stylax, he's got a lot of Stylax's dance moves. He's a good mover! I've never seen Ryan do anything like Grumio, ever. Sometimes he will look at you like that, that's the only time. That sort of Grumio look when I tell him to clean the bloody room and he doesn't want to. But generally he's a complete comedian. So no, I don't think they are like their characters, which is a testament to their ability as actors, really.

It sounds like you have some wild nights out.

You've got to really, when your days are like the ones we have! But it's great - the nightlife in Bulgaria is really good actually, and it doesn't hurt that, you know, the exchange rates are quite favourable. So we've probably seen most of Bulgaria's hotspots!

Describe Series 3 of Plebs in three words.

Series 3 in three words? Three words is not enough words. I want it to be a sentence. I like a three-word sentence. I'm going to have a think because I'll read this and think, 'That's bullshit! Those are the worst three words you could pick!' OK, here goes... "Plebs Series 3 - now with lions!"

Plebs Series 3 is on ITV2 on Mondays at 10pm.