“Because I’m happppy,” sings a slightly croaky voice in front of me as we approach the exit to the Arena’s downstairs backstage area.

“There you are there’s a sneak preview,” says Steve McFadden, otherwise known as EastEnders’ long-serving hard man Phil Mitchell, following his exclusive rendering of Pharrell’s smash hit.

If his character’s storylines in the soap are anything to go by, you would not expect to see Phil Mitchell’s face happily mouthing the words to this song.

When anything terrible has happened in the soap, more often than not he has been involved - he’s been shot twice for a start and has had more fights than you can count on your fingers.

But this Christmas, the man behind Phil is swapping Sharon and the Arches to play Fleshcreep, an evil henchman, in the Alban Arena pantomime Jack and the Beanstalk.

After training at RADA, he is no stranger to treading the boards but his true introduction to acting came from a moment many local market traders will identify with - shouting out to sell goods.

He explained: “I used to work selling stuff on the street. We’d tip up a couple of crates upside down and you’d get a suitcase and sell ‘tom’ which is jewellery and ‘funk’ which was perfume.

“It was the first time I ever learnt to stand up and shout.”

He likened yelling ‘THREE FOR A PAAAND’ to his potential buyers to being on stage and performing to an audience.

When he left RADA he dreamt of performing Chekhov and Shakespeare to the masses but stage work never seemed to happen for the trained actor. “I think there was a bit of snobbery going on; theatre was mainly for the middle classes. I probably fitted into certain types of productions. For whatever reason it just didn’t happen for me.”

But when one door closes another door opens, and luckily the phone never stopped ringing with TV and film jobs; he has worked ever since, most notably as Phil.

Playing one character for so long has been a pleasure rather than a problem and he rejects the notion of typecasting, merely accepting some people lend themselves to particular roles.

“I’ve said it before and I’ll say it ‘til I won’t be able to stop it, I’ve played a lot of characters and they’ve all been called Phil.”

He went on: “I’ve never played a ‘goodie’ once. I mean I look like a bad boy, my voice is quite strong. Just naturally how you get… not typecast, but cast.”

Naturally the topic of EastEnders and Phil’s extreme storylines crop up and I discovered the actor will go to great lengths to get a plot line perfect.

“When I did the crack story I spent a night with two crack guys. These two guys took crack, and I watched them, so I did my research.”

Although he describes panto as a ‘welcome relief’ from the regimented yet chaotic world of filming on the Walford set, the actor’s ‘research’ does not get forgotten when it comes to more relaxed roles.

“For me it’s not like any other acting job when you’re doing panto. There’s three elements that I like to bring: the character I’m playing on screen, who I really am, and the panto character I’m playing - it’s an amalgam of those three personas.”

Away from the Arena stage this Christmas, he is looking forward to exploring all the city’s restaurants have to offer with his family: “I love my food, my particular passion is seafood.”

Foodie, thespian, market trader – is there anything he can’t do? Apparently not, as he also offers to write an article for the Herts Advertiser before he leaves in the New Year.

And so we wrap up our interview, and I leave him to join rehearsals and become the villain once more.

He’s never played a ‘goodie’ but as I watched him cheerily sing Fleshcreep’s revised Happy lyrics and proudly show me his ominous panto outfit, I figured maybe he doesn’t want to.

The pantomime opens tonight at the Alban Arena.