Why Are stars bananas about pyjamas?

It’s not so much ‘Hello Boys!’ as ‘Goodnight Guys’ — as Michelle Obama is the latest to flaunt just-out-of-bed chic . . .

AT ALMOST 6ft tall before she even thinks about heels, Michelle Obama has the presence, the verve and the confidence to pull off the boldest of fashion statements.

But none of her wardrobe choices to date have matched up to the surprise of seeing her arrive for a talk at a Paris book store looking like she was dressed for bed in silky, striped pyjamas.

These were not, of course, just any old PJs.

Designed by London-based Roksanda Ilincic, their price tag is around £2,795 for starters, and a closer look reveals the fine tuning, such as the huge cuffs on the wide-legged trousers and the crystal buttons on the top, which nips in at the waist most flatteringly.

But even so, it’s a look you might think is more suitable for a night in with girlfriends than a talk before hundreds of people.

Yet this is one of summer’s hottest trends, with pyjama- style suits seen on the spring/summer catwalk at Dolce & Gabbana, Gucci and Chloe.

While men may groan — they are not, generally speaking, big fans of PJs on women, other than behind closed doors — women of a certain age are sure to cheer.

For this is an outfit that is modest yet effortlessly chic, the antithesis to the fashion for flesh-flaunting slip dresses or camisole tops — the styles that more commonly make it out of the bedroom and on to the red carpet. The fluid,

flowing fabric of pyjamas drapes over lumps and bumps (reflecting the flash of a camera perfectly, to give a pretty sheen).

The elasticated waistband is a dream and can be worn high at the waist or low on the hip, depending on your shape.

At 55, Michelle Obama certainly demonstrated the power of a pyjama suit for the mature woman with a dazzling insouciance — but she’s not the only celebrity to embrace the look.

Kate Beckinsale, 45, was recently spotted stepping out in New York in a pair of b l a c k- and- white striped pyjamas, teamed with black peep-toe heels.

Never one to let a trend pass her by, 45-year-old Victoria Beckham has also got in on the act, her silky pinkand-white chequered pair by her own label lends her a soft, almost cuddly air ( but these PJs will set you back £1,340).

Wonderbra postergirl of yesteryear Eva Herzigova, 46, may be more ‘Goodnight Guys’ than ‘Hello Boys!’ in her soft Alberta Ferretti set, but

that’s the beauty of this ensemble — grown-up women love it. They’re ultra- cool in every sense, for there’s no better fabric to wear than loose-fitting silk when your body temperature starts to rise. If you prefer a little more structure, you can always buy the designs that come with soft belts to emphasise the waist. Bear in mind, though, that before leaving the house in your PJs, there are a few rules to consider. First, the quality of the fabric. It has to be silk (or at least silky, if your budget is more aligned to High Street offerings from the likes of Zara, River Island and H&M).

There must be no cotton, flannel or winceyette. And no teddy bear patterns or hearts.

Think Coco Chanel — who first popularised wearing silk pyjamas as evening wear in the Twenties — rather than a teenage sleepover.

Juliette Binoche, 55, gets it just right with elegant monochrome set by Roberto Cavalli. Maggie Gyllenhaal, 41, looked effortlessly elegant in her floral Alberta Ferretti set with a matching belt.

The second rule? This is a look that can be pulled off only with a pair of contrasting, high-glam shoes. Michelle wore gold, opentoed sandals with an impressive heel, and it was high silver spikes for Sarah Jessica Parker, 54.

Liv Tyler, 41, wore block-heeled sandals with her Stella McCartney animal-print PJs. Salma Hayek, 52, tried to get away with platform trainers when she teamed them with her £3,000 pink Gucci jim-jams at last year’s Cannes Film Festival, but with less success.

Rule number three, and the most important, is to wear your pyjamas with pride. People will inevitably make jokes that you have forgotten to get dressed — but the point here is about having the confidence to dress for ourselves rather than for seduction.

And in that regard, Michelle Obama leads the way yet again, nailing the fashion liberation most grown-up women crave.