No one knows exactly how a Scotsman's tradition ended up as an international staple for the male wardrobe.

That motley mix of coloured squares once used to identify Highland clans has made its imprint as the must-have plaid shirt.

It is fast becoming a wardrobe classic as much as the crisp white shirt.

Just this month, American style magazine GQ put teenybopper heart-throb Zac Efron in one. He wore a silk Dolce & Gabbana midnight blue suit with a gingham print shirt by American designer Thom Browne.

Plaids are not just confined to shirts. American casual label Gap's checked cargo bermudas are the star item this season at its four stores here.

�'Plaid's high versatility can create different looks - from urban to preppy to rocker - with minimal effort,' says Bossini Singapore general manager Barbara Chan.

The Hong Kong-based clothing brand, popular for its casual and affordable togs, has joined labels such as Ben Sherman and Fred Perry in making it hip to be square.

Its summer collection, to be launched next month, features eight plaid shirts and a pair of cargo shorts, says Chan.

As fashion insiders note, the plaid fever is nothing new.

Vestan Low, assistant merchandising manager at Tangs, notes: 'Plaids provide a quirky alternative to the more common print such as stripes.

'The traditional plaids which were popularised by the grunge music scene in the early 1990s have been given a modern update and applied on various unexpected styles and cut.'

Others who are check mates this season include Japanese designer Junya Watanabe.

However, beware the tartan terror: Head-to-toe plaid can make you look like a blanket.

Cheryl Ann Lee, marketing manager of lifestyle firm Amnesty which handles preppy British label Fred Perry here, says: 'If you are wary about plaid, try something in a darker colour palette first, like green or blue, instead of going full-on in red.'

- Big checks

The women had a field day dressing up in boxy buffalo checks last fall with dresses, skirts, jackets, you name it. But the lads have always worked these macho-sized checks best.

However, instead of flannel fabrics which they normally come in, opt for cool cotton fabrics so you do not sweat it out like a roughneck.

- Small checks

Smaller plaids are more refined and look smart enough to be worn in the office.

Pair them with a slim-cut blazer and skinny tie for a dandified vibe, or work the look high-street style with a snug shirt with the sleeves rolled up.

- Muted colours

Soft hues of pale pink and mellow yellow can seem a tad too feminine at first glance, but these colours are perfect gear for hot summer dressing.

The best way to pull off the look is to dress it up with some dark denims or by layering it with a cardigan in a darker shade than your shirt.

- Bold colours

If you are not daring enough to try bright colours in solid blocks, break them up, such as matching devilish reds with purples or canary yellows topped with bright cobalts.

This article was first published in Urban, The Straits Times.