Tim Key: I was an unintentional model this week. Such things happen to columnists like me...

(Ping Zhu)

I got caught up in a bit of modelling work this week. It wasn't intentional. No contracts were signed, and no money changed hands either, which was a good thing. It took the pressure off. Relaxed and unofficial, on Wednesday evening – for about an hour or so – I became the face of a Soho pizza joint. And though that had never been my plan, I have to say I quite enjoyed the experience.

I was early for my singing audition that night and I'd spotted a quiet little pizzeria on a twee corner in Soho. The naughty stink of the melting cheese had lassoed me and hauled me in and soon an Italian-looking English girl was leading me to a seat – crucially – in the window. I ordered some kind of authentic Italian beer and a Margherita and sat tapping my pen into my notepad, wondering what I could write about column-wise. Occasionally I would look out of the window, too. Gaze at the festive humans as they bustled about the dregs of Christmas. My pizza came; saliva dripped from my fat, wet lips and sizzled on to its piping-hot toppings; I tucked in.

I go into a trance when I eat something as good for the soul as a pizza, and that happened now. I hacked off ear-sized chunks with my knife and fingers and stretched them into my mouth, the strings of cheese pinging as I threw my head back in the glory of it all. I'd put away about half of it before I opened my eyes to locate my beer. And it was now that I saw that, beyond my Peroni, I was being watched.

A small crowd of people had assembled and were peering through the window at me. Or at least some were. Others were looking at the menu. There was a stand-off. Me looking at them, my latest fistful of pizza hovering by my mouth; them plainly scrutinising me. What were they looking for? I blinked. More saliva fell on to my plate. I blinked again. And then I chowed back the pizza. And immediately, as if I'd fired a starter-pistol, in they came. Them, and another couple who had been watching, too, a bit further down. I was in my bubble, sure, but even so, it was blindingly obvious what was happening here: these people were coming into the pizzeria because of how much I was enjoying the food.

I'd never really thought of the window-fronts of pizzerias as advertising. But, of course, it's exactly what they are. Why spend thousands of pounds on a mural of a traditional Italian family getting lashed and guzzling calzone? Much better to slap a window up and get a portly columnist to openly enjoy a Margherita behind it. Nature's advertising. Like the star of my own animated billboard, I licked my lips and slapped my belly and rammed another slice in. If I'm the face of this joint, I thought, I'm determined to make a good fist of it.

I looked around me and noticed the place had really filled up during my 'stint'. I felt a great sense of professional pride and tried to get more folk through the doors by licking my lips more and pointing to my plate and nodding and thumbs-upping the waitresses. I breathed hard on the window, too, and wrote "the pizzas here are second to none" into the condensation. This was no longer a quiet, little pizzeria. Thanks to my campaign it was now rammed, as people from all walks of life pointed over at me and explained to anyone with an apron on that "I'll have what he's having".

I had finished my pizza now. I lifted my T-shirt up and pointed to my tummy as if to say "that did the job" and some workmen from across the road downed tools and strolled over, but by now the queue was going round the block so they wouldn't stand a chance. Just as Twiggy had done for M&S before me, I had turned round this innocuous Italian eatery's fortunes.

I wiped the corners of my mouth with a napkin and waddled to the till. It was time to discuss payment.