Then again, you could be one of those plain-T-shirt-wearing types who thinks a discreet label in the back of your neck, say Calvin Klein or Giorgio Armani, is all it takes to give you a daily dose of fashion Brownie points.
It's more likely, though, that the T-shirt you're sporting has a bit more character. A slogan perhaps. Something ironic and cool like "Je suis un pop star", or something unintelligible in Japanese characters, with an unlikely English translation printed next to it, equally cryptic of course, such as "Five Shaolin Masters". Then again, you might be wearing this summer's hottest, most sought-after logo, Oeuf, which means nothing more than... well, egg in French.
Why is it so achingly hip to wear an Oeuf? Because it means nothing. And yet it's nonchalant cool at its most meaningful. If no one knows what it means (because there is nothing to know) it makes you look effortlessly "in the know". It's telling everyone that you are an ambiguous creature, difficult to understand but intriguing none the less.
"Why would anyone want to wear a T-shirt with Gap splashed on it?" says Andrew Hartwell, 27-year-old creator and owner of Oeuf. "Why not create a T-shirt advertising something you know nothing about that doesn't make any sense?" Why not indeed? "In that way you create a new brand out of nothing," he explains.
"Then the T-shirt means whatever the wearer wants it to mean."
You might have noticed recent shots in the press of Oeuf-wearers Noel Gallagher or the Chemical Brothers, or perhaps watched Jo Wiley for a whole hour, presenting Channel 4's Glastonbury spectacular in a big Oeuf sweatshirt. Fabulous stamp of approval from the pop world? Great free publicity? Er, no, actually. It's the last thing Hartwell wants, such is his fear of the label turning from underground cool into dirty- word mainstream.
But it seems that Oeuf is slipping out of his control. "We've sold 1,000 T-shirts [of the style pictured]) in three weeks," he says. Great news? Hardly. And worse is to come. "We used to sell maybe 36 of one T-shirt style to shops, now they're buying in batches of 950," he worries.
Hartwell is only too aware of the sudden explosion in popularity of his brightly printed Oeuf clobber. "It no longer has the cult of the new, so we've been trying out other designs." Equally meaningless. Equally cool. How about a print of a big doughnut flying through space? Or a knight in armour with no face? Or what about the logo Homme Minus (a pun on Vogue's ultra-stylish magazine Homme Plus). "It's funny. It's horribly ironic, like saying you're the fashion equivalent of a loser," says Hartwell.
What if you don't get it, or, God forbid, don't want to be achingly cool? There's always a T-shirt that does mean something. Antoni & Alison came to fashion fame when they patented the first vacuum- packed T-shirts, apparently inspired over the bacon freezer when shopping in Sainsbury's. The duo was recently invited to take part in the NSPCC's powerful "full stop" campaign, to raise awareness about cruelty to children, by designing T-shirts which feature the simple graphic symbol of two arrows pointing to a full stop.
"T-shirts are the most populist piece of clothing," says designer Antoni Burakowski. "They're a simple blank canvas, perfect for getting across a powerful message and therefore raising awareness." The full stop T-shirts are available in any one of New Look's 450 stores, at pounds 9.99, pounds 3 of which go to the charity.
It's well worth popping along to Antoni & Alison's own shop at 43 Rosebery Avenue, London EC1 (or try the mail-order on 0171-833 2002 if you can't make it to London) and pick out a T-shirt or two from their vast boards.
You choose the print, colour, shape and size, wait 15 minutes or, better still, nip over to the cappuccino bar across the road, and when you return, Bob's your uncle, you have your own individual, take-away T-shirt, from pounds 27.50. The prints, by the way, are also deeply ironic: a packet of chewing gum with the print "Don't chew gum" - apparently popular with American tourists - and the beige T-shirts which read "I find plain exciting".
If you're not after puns or comical imagery you're lucky, because here anything goes. Dizzy floral prints, bright blocks of colour, stripes, spots, embroidered roses, and rows of numbers. Oh, and short sleeves, long sleeves, no sleeves, round necks, slash necks, scoop necks... the choice is yours.
Photographer: Anna Stevenson
Stylist: Holly Wood
Make-up: Firyal Arneil using Mary Quant
Model: Juliette at Select
Pale pink Japanese script T-shirt, pounds 25, by Duffer of St George, 29 Shorts Gardens, London WC2 (enquiries 0171-379 4660)
Khaki stripe sleeveless T-shirt, pounds 27, by Silas, from Shop, 4 Brewer Street, London W1 (enquiries 0171-266 5087)
Burgundy sleeveless T-shirt, pounds 45, by YMC, from Liberty, Regent Street, London W1; and Square, Bath (enquiries 0171-613 5293)
White floral vest, pounds 40, by Eley Kishimoto, from Liberty, Regent Street, London W1 (enquiries 0171-734 1234)
Pink T-shirt, pounds 30, by Oeuf, from Bond International, 10 Newburgh Street, London W1 (enquiries 0171-437 0079)
Navy `je suis un pop star' T-shirt, pounds 34, by Born Free, Browns Focus, 38-39 South Molton Street, London W1 (0171-514 0063)
Pink long-sleeve T-shirt, pounds 50, by Bernstock Speirs, from Ten, 10 Columbia Road, London E2 (enquiries 0171-729 7229)
NSPCC `full stop' campaign T-shirt, pounds 9.99, by Antoni & Alison for New Look, stores nationwide (enquiries 0500 454094)
Cashmere T-shirt, pounds 310, by Matthew Williamson, from Harvey Nichols, London SW3 (enquiries 0171-253 4200)