Kathy Lette: Phew! What a squawker!

She's glossy, brightly painted, an exotic parrot in vibrant plumage. Even her book jackets are lime and purple. And those smart one-liners just keep coming. The novelist Kathy Lette's jokes may be well-rehearsed, but why not? We all like a bit of pun, don't we?

The arrangement is that I meet Kathy Lette at an address in London's Temple, which, if you're into these things, is a blissfully historical sort of place, dating back to the 13th century and built around the old Inns of Court. Here, it turns out, she and her husband (the human-rights lawyer, Geoffrey Robertson, QC) rent a little flat on top of a particular chambers, which she uses as an office. Anyway, I'm early, so I sit on a bench outside – watching all the sombre-faced barristers pass by in their pinstripe suits of grey, black, blackish-grey, greyish-black, and (daringly) the kind of black that might, in the right light, even be navy – until it's time to go up to the fourth floor, into the flat, and... wow!

She's at the sink when I arrive, washing up coffee mugs in Marigold gloves, but, still, wow! A conker-glossy hairdo. Blood-red lips. Blood-red nails. Dangling heart earrings. Pointy stilettos. A dazzling Moschino outfit in shimmering aquamarine with a naughtily short skirt. It's like suddenly coming across a vividly plumaged, exotic bird that has somehow been blown off its usual migratory course.

I put this to her and she is pleased, I think. "Yeah, all the people round here have even got pinstripe underpants." I admire her Moschino. She says: "Well, if I was coming to interview you, you'd put on your best little Moschino frock, wouldn't you?" No, I say. I don't have a little Moschino frock. This is as jazzy as I get. "Oh," she says. "Is it? Your high-life visa has certainly expired, hasn't it?"

She doesn't say this spitefully. She may be a little perplexed, though. Nondescript just wouldn't be an option for her. Why be a drab, insipid thing in Gap, when you can be a great, squawking, room-filling macaw?

So, she makes me feel rather like a house sparrow. And a common one at that. But, still, I like her from the off, even though I am pitifully in awe. The Moschino. The legs! She has terrific legs. "Yeah, but they're the only good thing I have left." (Pur-lease, as she would say herself.) She is bursting with energy, and seems astonishingly keen to take me in under one of her psychedelic wings. "You must come to one of my little literary salons. You must! Do you know so-and-so?" Um... nope. "Or so-and-so?" Um... nope. "Oh." Brief pause, registering disappointment. Then: "Still, you must come. You must. It's more a girls' night in, actually."

A girls' night in? I perk up. A girls' night in, with champagne and face-packs and much hilarity? I've always dearly wished to be part of an in-crowd that does all that. I don't want to appear too pathetically keen, though. I'll try to come, I say. I don't add, of course, that any in-crowd that agrees to have me tagging along isn't an in-crowd at all. It's an out-crowd with tragic delusions.

Whatever, she's unstoppably talkative, which makes a nice change from most interviewees – what's your favourite colour? "I'm afraid I can't possibly answer that" – and something of a fabulous name-dropper, too. "Did you see the Booker last night? I'm so pleased for Peter [Carey]. He's a friend of mine. As is Ian [McEwan]... it was a bit of an evening. Deciding which party to go to... I'm sorry this place is so daggy... I don't have any luxuries in here, so that when I come, all I can do is work... look at the sofa, aghh! I sent Geoff to get a sofa and he came back with this lime thing... I'm good at getting down to it here, but not at home... books and babies don't go together. All the women authors we love – Jane Austen, Edith Sitwell, the Brontës, Dorothy Parker – none of them had babies..."

She has two children, a son and a daughter – Julius, 10, and Georgie, 8 – and is furious at the baby gurus for never saying how sensationally tedious it can all be. "Miriam Stoppard? Penelope Leach? What bitches! Whatever happened to mummy rights? They just don't tell you how boring it all is, particularly when your kids are larvae. It's better when they can talk to you and be amusing, but that larva stage... Sometimes, I'd get so bored doing creative things with Play-Doh that I'd grow a yeast infection as a change of pace."

I've heard this last line quite a few times before – have read it in almost every interview she's ever done, actually – but laugh anyway. It is a good line. The thing about Kathy, though, is that she does hang on to her good lines for dear life. Quite literally, I suspect. Still, best not bang on about it. I do very much want to do that champagne and face-pack and hilarity stuff.

To be perfectly honest, I've never really properly registered Kathy Lette before. Yes, I've been aware of her, flapping about noisily in the background, perhaps irritatingly, like a sort of sub-Ruby Wax, only from Australia and rather more conker-like. True, I'd clocked her novels in bookshops, but as they all come with acid-coloured covers and self-congratulatory, punning titles – Altar Ego, Foetal Attraction – I'd tended to run rather speedily in the opposite direction. Gosh, she loves her puns. You could drown in a sea of her "punnilingus". She is "Miss Quiplash", the master of "tongue fu," scourge of the British with their "stiff upper labia".

Have you, I ask, come up with a good pun-liner (look, it's catching!) lately? Well, she says, at the Booker do, "someone said to me, I've got to run now, but I've got a proposition for you, so I'll speak to you tomorrow. So I said: 'You should never end a sentence on a proposition'." Neat, I say. Yes, she says, adding: "Is it sick to quote your own jokes?"

Her latest novel is Nip'n'Tuck ("It'll have you in stitches" screams the blurb), which is a neon purple and lime job, about a woman who, approaching 40, succumbs to the surgeon's knife in order to hang on to her roving-eyed husband. Some of the gags are exhaustingly laboured – and who, you might ask, am I to say so? – but there are some good moments, too. She is particularly fine on women of a certain age who know that expensive creams made from the exhaled breath of ovulating whales (or whatever) are total rubbish, but still can't help themselves. "You seem to develop a chronic inability to say 'no' to Harrods beauty assistants," she writes. "Puréed pig erections? Yes please. Ground sheep embryos in a handy, handbag-size dispenser? Hell, yes..."

What, I ask, is your most recent ludicrous purchase? "Just the other day I bought an Eve Lom facial cleansing thing for about £40 or something. That's not even much, right? It's not like that Crème de la Mer, which is, what, £500 a pot? That's facial caviar. Can you imagine, though, living with a human-rights lawyer, and one minute we are talking about Third World debt and Taliban atrocities, and the next minute, I'm upstairs, going through my Eve Lom cleansing routine or examining myself in the mirror for butt buoyancy."

This isn't a new line, either. I've read this quite a few times before, too. Still, I laugh. It's another of her good ones, along with, say, babies and the law not mixing. "I'd say, 'come and help me change a nappy, Geoff'. And he'd have 250 people on death row in Trinidad – Muslims that he'd worked for six months, for free, to get off. In the beginning you're quite tolerant, but then, after a while, you think, 'Oh, let them die.'"

She is like a jeweller, one who keeps flashing her most dazzling trays at you even though you've seen them already, and are actually much more interested in the less highly polished items that might be lurking out the back. I do try to get out back, so to speak, but fail horribly. Perhaps I just don't ask the right questions. Or perhaps there is no "out back" to get to. By this, I don't mean she's shallow. I'm sure she isn't. It's just that the good lines have come to define her, and without them, she possibly feels she has nothing to perch on. She's rather phobic about appearing ordinary, I think. I ask her what she fears most.

"I have a fear of being boring. My commandment is: thou shalt not bore. I couldn't stand to be dull."

But what a chore, I say, always having to perform. How tiring. "I don't have to do it. I quite like it. It keeps me amused. I do have my long day's journey into shite, occasionally."

Oh?

"Yeah. I howl and punch and chew holes in the furniture and all that, but I don't want to be too indulgent. I don't want to be a whingeing whoopie. I would never do the whole shrink thing. I do think psychiatry is a waste of good couches. Why should I make a psychiatrist laugh, and then pay him?

"If I was in therapy, I wouldn't write. I get out everything in my writing. I always write the book I wish I'd had at the time I was going through something. My books are like manuals for other girls. It does exorcise your angst." Even this latest book? "At 39, (she's now 42), I was thinking of having breast implants. Yes, me! Because my boobs had sagged and gone down a cup size, after breastfeeding. You know, all that Meals on Heels." And there's that tray again.

What's your first memory of being funny? "I remember being the class clown, but the time I learnt I could use it to my advantage was when I was a surfie girl in Australia. You know those surfie girls? It's like growing up with hundreds of Elle Macphersons. Girls who are so unbelievably perfect. Tall, huge tits, curving in and out in all the right places. And there I was, this bonsai brunette. The girl whose cup didn't runneth over, you know? So I had to do something else. So I taught myself to be a motormouth, to verbally tap-dance..."

I wonder what truly matters to her. Or what hurts her, even. Has she read anything about herself, say, that's been really hurtful? "Oh, all the time. Journalists hate me." Do they? "Yeah, you know. Show-off. Loud-mouth. The puns. They're always going on about puns being the lowest form of wit. Well, if they were good enough for Shakespeare... And everyone is always going on about what a mistake it was, Geoff leaving Nigella Lawson for me. I get a lot of that. That's what it's gonna say on my tombstone: 'What the hell did he see in her?'"

She met Geoffrey Robertson in Australia, on a TV show, and immediately came to Britain to be with him. And, yes, he did dump Nigella for her. "She's perfectly nice, but I'm allergic to any woman who makes other women feel inadequate. Martha Stewart, she's my real hatred. How to make Christmas cards out of your old potato shavings... Women are meant to be so many women at once, and you can't do it. Domestic goddess, sex goddess, earth mother, the shoulder-padded career girl, trophy wife..."

Now, hang on, I say. You're railing against all the things you are, and have. The Moschino suits. The terrific legs. The house in West Hampstead, as well as the little flat in town. The famous husband. The famous friends. The bestselling novels. The girly night in-crowd thing. You make other women feel inadequate. I'm jealous of you.

She just can't see it, though. Or won't see it. She should, actually, be in Hello! Have you ever done Hello!? "Oh, God no. They did ring me to do it once and I said I'd do it as a spoof. Crap everywhere, house in state of chaos, yelling at the children. One of the editors agreed but then the head person found out and freaked." Sadly, I say, there's just no ironic typeface at Hello!. Still, it's worth it for the madly over-decorated nurseries all celebrities seem to go for when they've just had a baby. "You know those children are going to put themselves up for adoption very, very quickly," she says.

Plus, of course, Hello! understands that you just can't see Jane Seymour's dining-table from too many angles. She laughs at this. It's a very old line of mine. But I'm buggered if I'm going to be beaten at my own game.

In short, she is complicated but very likeable and genuinely warm. For every question I ask her, she asks me two, which does help me feel less pallid. She has, also, tackled some taboos, has come out and said that no matter how dearly you love your kids, time does not fly while helping them do a three-piece Spot puzzle for the 467th time. "More women are writing about it now. Naomi Wolf, Rachel Cusk. But they could do with a few more jokes."

She gives me a lift in her taxi part of the way. She would have taken me all the way, she says, but she has to take Georgie to Fun with Music or something. My last glimpse of her is in the back of the cab, waving a shimmering aquamarine arm and those fire-engine fingertips. I do hope the champagne and face-pack and hilarity thing comes off. I might even do the Moschino-macaw thing. After all, birds of a feather should frock together... (Oh God, it is sodding catching!)

'Nip'n'Tuck' is published on 26 October by Picador (£15.99)