Antony Hegarty laughs, half-hiding his face with embarrassment behind his loose black cardigan. �I used to be a go-go dancer,� he says. �People said I had nice legs.� Interview by Graeme Green.

By Graeme GREEN

It's an odd image, the singer-songwriter of Antony And The Johnsons giving it large on a podium surrounded by a writhing mass of ecstatic ravers. It's certainly not the first thing that springs to mind when you listen to his music. I Am A Bird Now, the album that introduced him to the wider world in 2005 and won that year's Mercury Prize, was an intensely sombre set of piano songs about loneliness, death and gender identity, all sung in Hegarty's distinctive sorrowful voice, like a world-beaten Nina Simone.

Before that, though, Hegarty was a radical, English-born, New York performance artist struggling to make ends meet - hence the dancing. "I can't say I was the most savoury go-go dancer on the block," he remembers. "I even wore a flowerpot on my head. This was at the Limelight club, a huge church on Sixth Avenue in New York before they closed it down because people were always getting killed there. In the mid-1990s, it was a techno hell-hole. But it was so futuristic, like being in Blade Runner. I really felt like it was the future."

The podium's loss is music's gain, but the transition from cult performer to pop star wasn't easy. "It was actually in Scotland that I kind of gave up," Hegarty recalls. "The last of the indie labels in the UK said they wouldn't release my record. All of them had said no, every one of them. I did a show that night in a coffee shop in Glasgow, and I remember thinking, I can't believe it, I've finally hit the bottom. It's never going to happen'."

The album finally found a home with Rough Trade and went on to sell over half a million copies, topping many end-of-year polls. Hegarty faced the odd situation of accepting the Mercury Prize in a room filled with all the record company bosses who had turned his record down. Perhaps their reticence was a case of not knowing what to do with an androgynous alien voice singing tragic ballads about breast amputation, abusive relationships and boys wanting to grow up to be beautiful women. In the end, it took the help of a few famous friends to sledgehammer his way in. Devendra Banhart, Rufus Wainwright and Hegarty's childhood heroes Boy George and Lou Reed not only sang on I Am A Bird Now, but also used their industry muscle to secure him a deal.

When I meet Hegarty at the Malmaison hotel in London, his room is a mess and the bed unmade. CDs, clothes, empty bottles and cups are strewn about, the debris from two days of interviews on a whirlwind tour of Europe to talk about his excellent new album The Crying Light.

Hegarty is a little messy, too. He answers the door barefoot, black hair flopping over his face. He wears what look like grey pyjamas under a worn black cardigan. He speaks slowly and softly, his voice low and quite feminine, the accent more English than American.

If his mournful songs and gender-bending photoshoots suggest an ultra-seriousness or otherworldly mystique, in person he confounds those expectations: he's warm, open, with a playful, quite camp and self-deprecating sense of humour, particularly when confessing past glories as his bald-headed former drag queen alter-ego Fiona Blue. Does he feel very different from his public image?

"People probably do expect me to be really melancholic," he says. "Sometimes I'm very serious and I think about things a lot; other times I'm very ridiculous and laugh a lot with my friends. I think I inherited a ridiculous sense of humour, possibly from English television. But it really just depends who I'm talking to. I've got a people-pleaser personality, where I'm always trying to mirror the other person I'm with - something I learned from moving around a lot as a kid."

I Am A Bird Now changed Hegarty's life considerably. He toured the world and his unique voice became a highly sought after instrument: he appeared as a singing convict in Steve Buscemi's film Animal Factory and cropped up on records by Rufus Wainwright, Coco Rosie, Joan As Police Woman and Bjork, singing two songs on her 2007 album Volta.

"She's so courageous, so gung-ho and full throttle," he says of the Icelandic diva, "it was a real challenge for me just to keep up. She brought me to Jamaica and we jumped into waterfalls for a while. She knew I was really exhausted after all the touring I did in 2005 and 2006, and so she rented this crazy place. It was wild. I'd never been anywhere like that. She's been a great friend."

Hegarty also joined U2, Nick Cave and Jarvis Cocker to perform at a Leonard Cohen tribute concert and toured Europe with Turning, a multimedia collaboration with visual artist Charles Atlas. More recently, he teamed up with New York disco collective Hercules And Love Affair - their single, Blind, becoming a crossover hit, their music soundtracking catwalks for Gucci, Versace and Chanel.

Between projects, he has found time to set up home in a new apartment in New York and to travel to Iceland, Antarctica and other landscapes that inspired his new album; all of which might explain why it has taken four years to write a follow-up to I Am A Bird Now, although Hegarty insists he's simply a slow worker and perfectionist. This time around, there are no guest stars - just Antony, with understated but beautifully detailed backing from The Johnsons and classical composer Nico Muhly's symphonic arrangements. The strange new songs are largely about nature, landscapes and the environment, suggesting Hegarty's been doing a bit of a Wordsworth.

"Inhaling the clouds and exhaling a poem? Not really. It's more something that, in retrospect, I realised I'd cultivated: a vocabulary and images reflecting the elements and the natural world. I was raised Catholic, raised to think that as human beings and as Christians we have different constitutions within our souls and that this world is just a workstation until we get to heaven. As I've got older and more confident in my own thinking, as a transgender person, as an artist, I really don't feel an alliance with those ideas anymore. So I was looking at what I have in common with the natural world, that I'm made of the same stuff, the same water and carbon and elements."

The new album is more outward-looking than the introspective I Am A Bird Now, but it's still about identity and finding connections. "They're songs about relationships between child and mother, child and father, child of the Earth; about my dependency on the Earth, physically, almost like a foetus in the womb, breathing in her oxygen. I like the poetic idea that the Earth is my mother and my parent, just to feel more a part of the world, because I tend to feel quite isolated. I was raised to feel quite separate."

Hegarty was born in Chichester, West Sussex, in 1971. His mother was a photographer, his father an engineer, their careers often uprooting the Hegarty family: "My father's work was always calling for us to move, so we just followed him around, little goslings". A move to Holland suited him, but later, the US proved harder for an outsider, an immigrant and a "gay kid" - although he does admit that the American experience made him who he is.

Hegarty crossed the US in 1990 to study Experimental Theatre at New York University. He teamed up with a Warholesque collection of artists, misfits and reprobates to form the experimental Blacklips troupe, performing "midnight musicals" and gory surrealist theatre at New York's legendary Pyramid Club. "It was toothless heroin-addicted trannies, drag queens, prostitutes, dominatrixes a colourful, lively bunch."

When he wasn't ending shows dressed as Charles Manson or God, Hegarty often performed as Fiona Blue. The character was, he laughs, hiding behind his cardigan again, based on the Alaska character from Lou Reed's song Caroline Says II and Isabella Rossellini's cabaret singer in Blue Velvet. "It was kind of art-school pretension and I had a dream of embodying the spirit of all that. I shaved my head, I wore " he drifts off and sighs. "I was young. I might have written f*** off' on my forehead."

By the mid-1990s, performance art was starting to look like a dead end, so he set about finding musicians to form The Johnsons, increasingly using theatre performances as an excuse to play his songs in front of an audience. He also found kindred spirits in the wave of musicians emerging from New York's alternative scene. His first album, Antony And The Johnsons, recorded with a New York Foundation for the Arts fellowship grant, was released quietly in the UK. Lou Reed heard a copy and asked Hegarty to sing backing vocals on his Edgar Allan Poe tribute album and tour The Raven.

Reed's support helped Hegarty onto the ladder, but the success of I Am A Bird Now on its eventual release still exceeded expectations. The album's impact was particularly interesting, given its unconventional subject matter. Was he surprised by people's openness to it?

"I'm always shocked," he says. "I remember doing For Today I Am A Boy at a festival in Ireland and the audience, I swear, were football hooligans, but I had them singing along at the top of their lungs. When it happened in Britain, I was like, What on earth is going on?' It challenged me - it made me question if some of my own ideas were outdated, ideas about my sense of separateness."

Hegarty has talked often about how his childhood idols Boy George and Marc Almond communicated bold ideas about gender and sexuality in their songs and images, describing them both as "warriors". Does he now feel he too is a warrior or role model, his image and lyrics pushing culture forwards in a similar way?

"Maybe, in my teeny-weeny demographic," he says, hesitantly. "I've been quite vocal about being transgender and I identify myself as being transgender. Within that, I still present as male. It's not particularly provocative, but I'm introducing a vocabulary. It's a small step. So in another five years, maybe someone who identifies as transgender or lives in some state of gender variance can be embraced more naturally.

"I think things will keep slowly evolving. People are starting to realise more and more that trans-gender kids are just as much part of the family as all the other kids. I think 95% of families that have transgender kids feel this myth that they are created somehow somewhere in adulthood; but the fact is it's really about kids that are three or four years old, kids that have been identified as different from when they first said a word."

So what next? As well as possibly venturing further into dance music, Hegarty is keen to write soundtracks for films. He also hopes to return to his roots with visual and performance-based work, and there's talk of a covers album which could feature any one of the funereal reworkings of songs he has performed since his early show days: Lou Reed's Candy Says, a surprisingly emotional reanimating of Gloria Gaynor's done-to-death karaoke classic I Will Survive or, from recent concerts, a committed new take on Beyonce's Crazy In Love. "I fear the day I get a cease and desist' from her people," he half jokes.

His immediate future, however, will be dominated by touring, something he's looking forward to, though he's cautious about overdoing it like last time. The tour will include a Scottish date but, seeing as it was Scotland where he nearly jacked it all in, is he looking forward to being back here?

"I remember doing some really good shows in Scotland. I did almost get killed at one, though, when I said to the audience that Liz Fraser Scottish singer with The Cocteau Twins is one of England's national treasures. They all went Boo! Boo!' It was so humiliating. I won't make that mistake again."