He’s Captain Jack in Torchwood, he’s the host of Tonight’s the Night and he was a regular on Desperate Housewives. Donal O’Donoghue meets the one-man gang that is John Barrowman

We’re barely in the room when John Barrowman is already changing the scene. “I don’t like dark rooms”, he says, looking for a light switch. He also doesn’t like big empty rooms. But there’s not a lot he can do about that, apart from perhaps hanging a banner outside the door, proclaiming that the all-singing, all-dancing John Barrowman will be performing here later. And in a way he already does – perform, that is.

Barrowman is a man in perpetual motion. He’s also preternaturally good-looking in the flesh – like he’s been cut out of his TV shows. His hair is coal black, his tan is Malibu bronze and his teeth are exceptionally white. Built like a back-row (his arms bulging, his torso trim) the 44-year-old is chattier than a wound-up parakeet. But what else would you expect? Having recently wrapped the fourth season of Torchwood, in which he reprised the role of the Captain Jack Harkness, Barrowman has just released an album (The Best of Barrowman) and his new stage show comes to Ireland next month. It’s called simply, John Barrowman.

Today, he is limping slightly having recently hurt his back. How did that happen? “Oh that’s a very personal question”, he fires back and laughs, a man who doesn’t seem to know where the off button is. He says that he owes his prodigious work ethic to two things. “Firstly it’s my Celtic background”, he says. “Now it sounds terribly condescending when someone says something like that. But my grandfather, on my mother’s side, was Irish. His name was Andrew Butler and he came from County Clare. In fact, my niece is named after the county, that’s Clare spelt the same way. What I’d love to do, and I’ve spoken with my manager in this respect, is to make a programme researching my Irish roots to see how strong they are.”

Barrowman’s manager and business partner, Gavin Barker, sits in a nearby chair. Together they run Barrowman-Barker Productions, the company behind Tonight’s the Night. If Barrowman is a natural-born showman, he’s also a through-and-through businessman. But showbiz was always in the blood. “My grandmother and her sister were vaudeville hoofers in the Glasgow area”, he says. “Further back, my mother’s great aunt, I think, was Isabelle Bailey, a very famous opera singer throughout Europe.” Even so, he had other ambitions as a kid.

“The only thing I ever wanted to do was to be an airline pilot”, he says. “But then I discovered that I just liked the men in the uniform hahaha! It had nothing to do with wanting to be a pilot and it wasn’t until puberty I realised that there’s something different here. I have always wanted to perform though. From the age of four, I remember going to the record store that my mother worked at in Glasgow and I would stand on the counter and sing the Top 5 to whoever would come in. When I was a kid I wanted to be Lena Zavaroni, who was then the big winner on Opportunity Knocks.”

He grew up loving sci-fi and still does: from Star Trek to Battlestar Galactica to Doctor Who (in which Captain Jack Harkness made his TV debut). With the latest season of Torchwood – a US co-production featuring many glitzy guest stars including Bill Pullman – he was like a kid in a sweet shop. “For goodness sake, I fancied Bill Pullman when he did Spaceballs”, he says. “I thought he was a hunk and I told him that. He went (adopts gravelly Pullman accent): ‘Oh wow, the Barrowman loved me!’ ‘Loved you?’ I said, ‘I still do!’ He would joke with me after a scene, saying: ‘You were loving me there, weren’t you Barrowman?’ And I was like: ‘Yeah Pullman, I was loving you!’”

Will there be a fifth season of Torchwood? Barrowman is briefly stumped. “If there’s a pause button, we’ve pushed the pause button now because we don’t know what’s happening”, he says. “I would love to do a new series and I will play Captain Jack as long as they want me to play Captain Jack, but it’s in limbo at the moment and beyond my control.” He’d love to see his creation on the big screen. “I think that Torchwood, more so than Doctor Who, lends itself to being a big film because it’s more adult”, he says. “Now if it was Doctor Who with David (Tennant) playing the Doctor – I’m going to get in trouble for saying this – I’d happily do a film with him.”

He first met his partner, Scott Gill, some 17 years ago (they became civil partners in 2006). It was in the dressing-room after a stage production of Rope in which Barrowman had a nude scene. “I told him afterwards that he’d seen everything when I was on stage”, he says. “It was seven minutes of me naked.” Their first date, one year later, was a somewhat unusual set-up as Cher was also there. “Hey, it wasn’t a threesome”, he says and laughs. “There were more people there! Cher pursued me, not for any romantic reasons. She was thinking of doing Sunset Boulevard. But when she rang me up, I said to her, ‘Well actually I have a date tonight. It’s a guy I really want to see.’ And she said: ‘Honey, you’re going to turn down Cher to go on a date with somebody? For Chrissakes, bring him along.’”

He and Scott have been together since then. What’s their secret? “I wish I could give you a formula because then I could put out another book about how to keep a relationship together”, he says and laughs (Barrowman published his autobiography, Anything Goes, in 2008). “In a way, I put it down to not expecting much if that makes sense. There will be times when there are bumps on the road and we’ve had those bumps. So it would be very easy to say, ‘that’s done, we’re over!’ But why ruin what we have had for that long just because of some little flirtation or stupid incident that happened? We look at things realistically.”

As for the show in Dublin, JB is not shy of bigging it up. “I guarantee that you will be entertained”, he says, insisting that it will appeal to everybody over the age of seven. “It’s a fantastic show”, he says. “I write it myself.”

If John Barrowman the show is anything like John Barrowman the man – and I can’t imagine it will be anything else – then expect to leave the theatre with your head in a spin. “I love what I do and the day I’m not enthusiastic about it is the day that I quit and retire.” I can’t see that happening for some time yet.

* John Barrowman is at the Grand Canal Theatre on November 10