Delicate layers of chiffon look lovely on the hanger. But beware of ruining the look with the wrong underwear.
Now here's a novelty: underwear as underwear. You've done the Madonna thing and worn your pointy, conical bra out on its own; you've done the Hollywood petticoat thing and worn your slip showing. All there is left to do now is wear your underwear as... underwear. And now is the time to do it.

Fashion's love affair with sheer clothes began in 1968 when Yves Saint Laurent showed chiffon tops with nothing underneath. Then it was shocking. Now there is barely a catwalk show without a bit of bare flesh thinly veiled by lace or fine mesh. The shops are full of flimsy wisps of see- through lace, delicate layers of chiffon and barely there films of finest organza. They all have one thing in common: they do not leave much to the imagination and are most unaccommodating if you happen to be wearing your old vest that turned pink and blue tie-dye in the wash or, for that matter, your practical new G-string.

Sheer clothes are all very pretty on the hanger but they rarely come with anything to wear underneath. Collette Dinnigan, the Australian designer whose lace dresses and tops are racing out of Liberty, is the exception. For every piece of fragile lace, there is a little something designed to be worn underneath it. Few other designers, and certainly not the high street, are so thoughtful.

Forget cellulite, the odd bit of flab and your modesty. What you really need to worry about when wearing sheer is the state of your underwear. Few women are brave or flat-chested enough to wear nothing underneath a slip or chiffon, whatever fashion magazines might say.

At Knickerbox, spring's sheer clothes have been a dream. Buyers have been revving up for a season when women will be buying pieces specially to wear underneath a particular dress or skirt. "It's all about clean lines or no lines," says Chris Hall of the underwear chain. The new move in bras is for the seamless, moulded variety. And knickers are either so minuscule that you like you aren't wearing any, or so huge that they look like hot pants. The best thing about the sudden acceptability of big knickers is that you can go for the variety boasting "control panels" and take the opportunity to wear the next thing on from a panty girdle and be fashionable with it.

In the wake of Prada's big pants that cost more for one pair than most people's knickers for the year, Hanro has the perfect pair in softest cotton for pounds 14.50. They solve the problem of what to wear underneath a pair of sheer or semi-sheer trousers perfectly.

What you need to avoid when wearing sheer clothes is looking as though there is some mistake and you don't realise your underwear is showing. You have to make a feature of it. A very modern idea comes from Monica Zipper, the designer behind Monix and the revived Biba labels. She has created the Slip-on, a tube of 70 denier stocking fabric that varies in width from a bandeau to a full-length skirt. Slip-ons are designed to be worn on their own, but they also work really well - especially if your body isn't as svelte as it once was - underneath anything sheer. The bandeau doesn't have fiddly straps and works perfectly instead of a bra underneath a mesh shirt, while the short skirt length is another alternative to the big pants to be worn underneath a sheer skirt. Slip-ons range in colour from "nude" to brown, plum and black and start at pounds 5 for the mini-skirt.

For those who need a bit of underpinning, Marks & Spencer has the answer: a Dolce e Gabbana-style underslip with underwired bra is just the thing to give yourself a bit of support and shape under a see-through dress. Warner's also have a range, appropriately named after Marilyn Monroe, featuring underwear with "moulded" bra cups (made out of foam to reduce nipple show-through and increase what you've already got) in satin, silk and lace. Colours range from red and gold, to "powder puff pink" and even the odd animal print.

For something a little more subtle, Warner's also have the Not So Innocent Nudes range, with seamless underwear available in six skin tones from shell pink to blackn

Stylist: Charlie Harrington

Hair and Make-up: Alex Babsky

Model: Ailsa @ Models 1

Right: Sleeveless lace shift pounds 385, and slip underdress pounds 135, both by Collette Dinnigan, Liberty, Regent Street, London W1

Far left: Embroidered sheer net shirt, pounds 22.99, by Oasis, 292 Regent Street, London W1 and stores nationwide; Cream lacy camisole, pounds 39, by Marilyn Monroe by Warners, available from major department stores (enq 01159 795 796)

Centre: Sheer black trousers, pounds 94.50, by Ghost, 13-14 Hinde Street, London W1, and Question Aire? 78, The High Street, SW19; bandeau top, pounds 10, by Slip On, Switch, 22 Inverness Street, London NW1, and Hervia, Unit 6, The Royal Exchange Arcade, Manchester, (enq 0171-485 5926); big black pants, pounds 14.50 by Hanro, Harvey Nichols and Harrods, London SW1; black velvet flip-flops, pounds 160, by Gina, 189 Sloane Street, London SW1

Left: Shirt dress, pounds 135, by AO by Ally Capellino, Selfridges, Oxford Street, London W1; Square, 3-4 The Corridor, High Street, Bath; underwire nude slip dress, pounds 20, at selected branches of Marks & Spencer