It can be tricky getting noticed when you publish your first novel, but something tells me that Karen Mcleod isn't going to have too much trouble. For one thing, her book has a title - In Search of the Missing Eyelash - that, once heard, is impossible to forget. For another, there is her CV, which is somewhat unlikely. Mcleod is a 35-year-old air stewardess, who lives in Penge, an obscure corner of south London. Moreover, when she is not criss-crossing the Atlantic, serving hot food and cold beverages to grumpy business-class travellers, Mcleod works as a performance artist, putting on shows in which she disguises herself as a drag artist (ie, she does her best to look like a man dressed as a woman) and lip-synchs to her favourite camp anthems. And, as if all this were not enough, her book, which is published by Jonathan Cape, better known as the home of Ian McEwan and Martin Amis, carries a passionate puff from the woman who discovered it, novelist Ali Smith, winner of the 2005 Whitbread Novel of the Year.

'It's tremendous!' reads the quote. 'It's so good about loneliness and want. Such a mix of hilarious and poetic... pretty cunning and very satisfying.' Intriguing? I think so. Why else would I be here in Penge? It's a place that I've always thought of more as a concept (the embodiment of suburban living - of greying pebbledash and yellow chrysanthemums and gleaming Vauxhalls) than as, well, an actual destination.

Mcleod meets me at the station, and walks me to her flat to feed me Victoria sponge and herbal tea. She lives at the top of a neat Sixties-looking tower block just like the one in the children's programme Mary, Mungo and Midge and, from her window, you can see all of Penge, with its neat red-roofed houses and identical - from up here, at least - front gardens. It's quiet and still, and not only because we are so high up: occasionally, a (possibly gleaming Vauxhall-type) car will drift by but, otherwise, the only movement is that of the trees rustling in the breeze. Mcleod grew up in Penge, and her parents and sister still live close by (next door to one another, in fact). 'Yes, it's all very conventional,' she says, with a throaty laugh. 'The only unusual thing about our family is the fact that my parents are still married; everyone else's seem to be divorced.' Does she like living here? 'Oh, I love the sense of the community, and wanted my book to have that sense of community, too.' Sometimes, she forgets just how conventional her parents are. The other day, at their place, she admired, out loud, her new nipple tassels. '"Aren't these lovely?" I said to my dad. The look on his face. "You don't wear them do you?" he said.'

Mcleod is lovely to look at: buxom, with creamy skin, enviable hair and a deep voice. She also has the endearingly straightforward manner of one who cannot quite believe her luck. It was never part of her plan to become a writer, at least, not the kind with a capital 'W'. But her performance career never really took off in the way she had hoped, and her day job, which she'd originally intended only to be a short-term thing, was starting to make her feel 'diluted, dead, brain dead'. So she started writing and attended a couple of Arvon Foundation creative-writing courses. The second of these, in Devon, was being taught by one of her heroines, Ali Smith. 'I had these two chapters, which eventually became the first two chapters of my book. I thought they were quite perfect! But I was so nervous of meeting Ali, so I slid them under her door late one night. The next day, she came to me and she said: "I love them, and on Monday, I'm going home to email an agent I know who is putting together a new fiction list. All you've got to do now is write the rest." I didn't know what to do! Everyone else on the course was very ambitious, and I didn't know whether I could share it. I didn't want to ruin their experience.'

She spent the next nine months writing - 'it just sort of flew out of me' - and finished the book last April; by May, she had a publisher. It's not hard to see why. Quite apart from the fact that she is a publicist's dream, she has written an unusually striking first novel - rather weird, I think, though I mean this in a good way. It's about a girl called Lizzie, who is lonely. Her parents aren't around and her brother, who thinks he's a woman, has disappeared. Worse still, the love of her life, Sally, has gone off with a man with a fat neck. She only seems to have one friend - Petula, who lives in the downstairs flat - but she is a bit too self-obsessed to be of much use to the seriously love-sick. And so Lizzie starts to stalk Sally, donning a beret and mac like some crazy detective, and breaking into the house she used to know so well where she collects fluff from the bathroom and pubic hairs from the bed. This stuff is 'proof' that Sally's life is going on without her. Lizzie needs proof because her grip on reality is growing confused. Odd things are happening, including a phantom pregnancy, discovered after a night on the tiles in Brighton with Petula. Is Lizzie about to be responsible for the second virgin birth?

Mcleod doesn't have a transvestite brother, but she did once have a phantom pregnancy. 'Yes, that's the one big autobiographical thing. It seems like a dream now. I was living in Nantes at the time, and a doctor examined me and said, "Yes, you're pregnant, but we'll do a blood test anyway". So I had 24 hours of believing that I was pregnant having not had any sex with a man. I thought I was the new Virgin Mary. I'd say to friends: "I'm not religious, but surely He wouldn't choose somebody from Penge!" I stayed up all night, worrying what I was going to tell people. I decided that I would go and live in a wigwam in Peru, or something. I sort of lost it. It was quite mad. Surreal. But then I went back, and they told me I wasn't pregnant, after all. I felt rather disappointed by that point, because I'd got my head round it.'

But why had this happened? 'I was in love with someone who wasn't in love with me. It was my first real love with a woman. I was spurned, and all this emotion seemed to take on a physicality in my body. It's incredible what the body can do. Mine swelled up, and I felt nauseous in the morning. I ignored it for ages. This was before the days of date rape, so I just sort of thought that maybe my love for this woman was so strong, it had formed something real in me.'

Mcleod's mother is a dinner lady turned nursery teacher, and her father is a retired insurance broker; she was the first person in her family to attend university. She did a fine arts degree, specialising in performance and film; her degree show was a piece called 'I Am a Drag Queen', which she later took to the ICA. 'I had a filing cabinet that I'd scoured so that all the paint had come off it,' she says. 'At the time, I was keen on welding, so I cut a hole for my bottom, and made a couple of arm flaps, and had a TV screen as my head. It was like a dismembered body. I'd sing my favourite, Shirley Bassey's 'I Am What I Am', over and over, so you could see the sadness of it. I didn't know what I was doing, but at the time, it all made perfect sense.'

Where did it come from, this interest in drag queens? 'It came from watching Victor Victoria. I'm a massive Julie Andrews fan. I felt limited by being a woman, and I loved drag shows, and I wanted to do them. I was unsure of my identity. As a gay woman, you were not allowed to be feminine. But I loved wearing Seventies dresses! In lesbian bars, I'd get called a fag hag because I wore lipstick. I couldn't understand it. I didn't want to look butch.' For her 30th birthday, she threw a themed party: 'Come as what you wanted to be'. Mcleod, of course, did her drag-queen bit. As she tottered up Charing Cross Road, she heard two girls say to one another: 'Have you seen that man?' She was thrilled; she'd pulled it off again.

It was not always so easy. After university, unable to find a job in art, Mcleod went to live in Australia. 'To Sydney to be a drag queen!' Unfortunately, Sydney drag queens are ferocious. They did not want a woman on their patch. 'There was this charity night, and I was going to perform. I went into the changing room. None of them would speak to me. The looks they gave me were not nice. But I'd been rehearsing. I was going to do it anyway.' Once on stage, though, they pelted her with bread rolls. She never did it again, and returned to London a year later, still none the wiser as to what she would do with her life. 'I was living back at home. It was my mum who suggested the idea of being an air stewardess. I hated it. I felt as though everyone was looking at me without knowing who I really was. People treat air crew as dim. You're not a human being. I once heard a lady in business class say to her friend: "If my daughter did that job, I'd be devastated." I wanted to shout: "I've got a degree!"' Feeling her real life slip away from her, Mcleod began performing again, this time at Duckie, the weekly performance club that is held at the Royal Vauxhall Tavern, London's longest-standing gay venue.

Mcleod has worked as a stewardess for rather longer than she expected. 'Time just goes. I've become quite fond of the smell of the galleys, that's how long I've been doing it.' Is it a lonely life? 'It can be, though there's also a big partying culture. You do feel on your own if you're having a hard time at home, and then you go away and sit in a hotel room. There've been a few suicides. People get sick of you being away all the time. The parties I've missed!' Do her colleagues know about her other life? 'Yes. The gay guys all got it. The stewardesses thought I was a bit weird.' What her two lives have in common is that, for both, she must wear a uniform; her costumes, she tells me, act as a kind of shield, allowing her to perform - be it with her trolley, or while lip-synching - at the same time as they make her invisible (people stare when she's in drag, but no one can tell what the person in the wig really looks like). Still, she's had her fill of seatbelt routines and miniature pretzels; she would like to write full-time.

Her parents have never seen one of her shows, and it took her a while to tell them about her sexuality. As a child, she didn't know gay people existed. 'The first time I did was when I saw Nigel and Colin kiss on EastEnders. I was at a girls' school with very intense friendships, so all the other girls were doing the same. Then they started having boyfriends. I felt I should have one, too, so I tried. But it was boring. I didn't know what all the fuss was about. Poor thing. He used to try all sorts of things to woo me, but I was really mean to him. I didn't have any interest at all, while I secretly lusted after my best friend. Then, during my foundation year, I made friends with someone who is gay, and she took me to clubs and it was very exciting to find this new world. But even then, I hadn't told my parents. I thought they'd disown me. I told my mum when I was 21, though I didn't use the word "gay", which led to some confusion. She was always telling me news about people from school, who was getting married, or having children. I was getting so angry. I said: "I'm not like that. I don't like men, I'm not going to have children." I do remember crying, and she did, too, but I think she thought it was a phase. She said: "Don't tell your father because he'll die of a heart attack." No pressure on me, then!'

A few years later, though, Mcleod was taking part in a lesbian beauty contest organised by Amy Lamé, another Duckie regular, and was interviewed by a Sunday newspaper. 'I told Mum it was an alternative beauty contest, and I thought I was safe because they never got that newspaper. But my sister did. She called me, and said: "Mum's just thrown the newspaper in the garden. It's still there." I was sick. Mum didn't speak to me for a few days. But then Dad was out in the garden picking his runner beans, and he said over the fence to my sister: "How long have you known about this?" "A few years," she said. He said, "Well, so long as she's happy." Everyone knows around here now, and no one cares and, at work, I've always been very open. There are a lot of lesbians there who are reluctant to come out; some of the women can be a bit bitchy because it's an ultra-feminine way of life. They accept all the gay men, but they think lesbians are disgusting. But then I've had others say to me that they want to try it, like it's a new top. I've had offers for just one night.'

For the past year, Mcleod has been seeing a girl called Minnie, and it was Minnie to whom she read large sections of In Search of the Missing Eyelash out loud. 'It's a voice book, so if you read it out loud, you can tell straight away if something is wrong.' (Minnie has also replaced Mcleod's mother as the significant other who can take advantage of the massive reduction she gets on the cost of flights - so it must be serious.) Meanwhile, she is at work on her second novel, about a man who leads a double life. A transvestite? 'Yes, a transvestite!' But it's hard to concentrate when you're still publicising another book, and she is finding the going tough. 'I don't even feel I can call myself a writer. The other day, I went into the Crystal Palace bookshop. I told them I was a local writer. He looked at me as if to say, "Here we go - another one". It was only when I mentioned Jonathan Cape that he changed.'

If nothing else, there's something delicious about the idea of Mcleod - with her giant wigs and her Julie Andrews obsession and her women characters who get rudely drunk and pee in the street - being touted as a local author. I think this all the more after I leave her and descend to the street. China ornaments in windows; net curtains; a strange hospital for teddy bears. This is not, by rights, where a gay air stewardess-come-drag-queen-come-novelist should be living. But it pleases me mightily that it is.

· Karen Mcleod's In Search of the Missing Eyelash is published by Jonathan Cape on 7 June, £11.99