David Gandy has invited me round to breakfast at his pad in Fulham. I'm bringing the patisserie; he's bringing the million-dollar face and body, with which he made such an impression reclining on a dinghy for Dolce & Gabbana's Light Blue advertisement. He answers the door looking home-casual – his feet are bare – and gives me an overpowering smile: chin down, brow furrowed, eyes blazing. He really should charge for that smile.

Instead, he is launching his very own iPhone App, the David Gandy Style Guide For Men, with hints for those who don't look as good in a dinghy. He is on a mission. 'I could not bear seeing another bad tie!'he exclaims in a voice that has a comfortable Essex swing and the tiniest hint of a lisp. The body is divine, but the voice is
distinctly human.

He is living the male model's dream in this small, stylish bachelor flat, crammed with antique cricket bats, Rolls-Royce headlamps and French carpenter's drawers. The bathroom is stocked with Kiehl's and Aesop products, and he uses a badger-hair shaving brush. There are vintage wooden skis propped near the front door, as if he might grab them at any moment and slalom down the stairwell. He gets all these treasures from Sunbury Antiques Market in Middlesex, arriving at 7.30am to snap up bargain leather portmanteaux. Today, for our mid-morning appointment, he has lit some candles, bless him (masculine black Diptyque Baies), and put on a playlist that jumps from The xx to Tony Bennett. The place is spotless, though he doesn't have a cleaner ('It's too small to justify, isn't it?'), but he hasn't tidied away the white canvas floppy dog an ex-girlfriend, a model called Chloe Pridham, gave him that he seems rather attached to. In the corner of his sitting room is a stack of magazines with his face on the cover. Pictures of his style inspirations, as seen on his App, are pinned up beside his desk: Steve McQueen working a cardigan; Jude Law with a skinny scarf and trilby; Tom Ford. Brad Pitt has not made the cut. 'Great guy, but would you wear what he's wearing?'Nor Johnny Depp, nor Russell Brand –'He's got a look, but I wouldn't suggest people copy it. This is about how to dress classically, about how to get a suit tailored. A suit from Marks & Spencer can be adjusted from £40 – it runs an in-store service and so does Reiss.'

Next we head to where the magic happens: David Gandy's bedroom. This is where he throws together a perfect outfit. The dιcor is a symphony of wood – old oak wardrobe, priapic mahogany bedposts. The elephant in the room is the huge framed photo of him, propped against the fireplace, which neither of us mentions. He shows me a few favourite pieces: 'my Guccis'– shearling-lined leather slouch boots (right) which, on him, are winter in New York, but would make most men look like a Sherpa. Then there's his Dolce & Gabbana leather aviator jacket lined with sheepskin that would have cost 'about $6,000'
if Mr Gandy hadn't been rather a favourite of
Stefano and Domenico. He's had the jacket about four years and 'nearly cried'when he ripped it in New York in a Zoolander-style accident: he was getting out of a taxi with his hands in his pockets when his friend mistakenly slammed its door in his face; he couldn't get his hands out of those deep pockets in time to protect himself. He had eight stitches and a broken nose. The jacket was torn, but has been invisibly mended by D&G, better than his face, which still bears a scar.

There aren't many colours besides a cobalt blue Balenciaga T-shirt, bright as a Nice sky. Colour is Gandy's Achilles heel: 'I'm slightly colour-blind. I bought some lovely grey trousers, which my friends insisted were green. “You look like a leprechaun,” they said, so I went home and changed.'

The inside of a gentleman's wardrobe should probably stay between him and his valet, but somehow here I am inspecting Gandy's tie rack. His favourites are all skinny or middle width ('I do like a mid-tie'). Stand-out numbers include a velvet bow tie by Dolce & Gabbana and a discreet blue pattern by Peckham Rye, as well as a long, skinny, pure white tie by Spencer Hart of Savile Row. But what's this? It has traces of make-up in tan rough-and-tumble marks. He laughs sheepishly and says he wore the tie at Elton John's Grey Goose charity ball. It looks like it was quite a night – although it could be his own make-up... 'I didn't want to go for white tie and tails so I put this spin on it – a more 1950s look. There's a dress-code cracker on the App, because men get weddings so, so wrong.'

Gandy's style is, I suppose, a new, inspired formality: dressing up for fun rather than to conform to social codes. He is proudest of a chocolate velvet suit he bought from Dolce & Gabbana before he had a contract there. Only about 12 were made, and he feels it was worth the eye-watering price. 'My parents aren't clothes people – they didn't hand anything on to me,'he says, and then considers his style legacy to the future: 'I like to think my nephew, or maybe a son, will want my aviator jacket one day.'
davidgandystyleguide.com