“Do you want to interview Heston Blumenthal over dinner?” I’m asked, and before the question’s finished I’m in my coat and out the door.

Getting a reservation at Heston Blumenthal’s place is harder than a banker’s heart. The Fat Duck at Bray was the only restaurant in the country to score a perfect 10 in the 2009 Good Food Guide and Heston’s flare for food alchemy means punters have to have the booking line on speed dial to be in with a shot of securing a table. Being sent there ‘on the job’ seems too good to be true.

And it is. The first clue is the massive coach packed with journalists that comes to collect me. The second is the fact that we pull over at a service station. It’s not the Fat Duck we’ve been sent to but Heston’s other venture, the re-vamped Little Chef, at Popham in Hampshire. So close. So very close.

The gourmet dining experience is out the window but there is some comfort in the glitzy showbiz reception we get as we disembark the hack-bus. Blinded by paparazzi flash bulbs, I feel like Britney Spears. Inside it’s even more glamorous with genuine, bona fide celebrities like Anneka Rice and Kevin McCloud sipping champagne and ordering burgers in the faux-leather booths.

I once forced my parents to dine at Little Chef for a whole week because you got a free lolly for finishing your dinner. That was our last UK holiday. The look on the celebrity faces is like the look on my mother’s face. They’re thinking of those dingy Little Chefs of old with yellowing formica, twee curtains and food so greasy you’d need to wash your hands with Clearasil.

As Heston’s discovering in his debut Channel 4 programme, Big Chef Takes on Little Chef, changing people’s perceptions of the chain is no mean feat. Little Chef is one of those classic British institutions that we’d be gutted to see disappear, but never actually visit, though if Heston has his way they’ll all end up like this Rolls Royce of a roadside caff.

Thanks to design guru, Ab Rogers, the Heston Little Chef is actually pretty swish. The ceiling is decorated with blue skies and seagulls, the toilets tell you jokes and there’s even board games to keep the kiddies (and grown-ups) amused.

I wait for my table in the coffee area with no-holds-barred critic, Jay Rayner, laughing girlishly at his anecdotes of being a sex columnist for Cosmo. I point out the girl from Balls of Steel to the man next to me. “She’s got a hole in her tights,” he says. She has as well. “This really is the high life,” I think, then, at the height of my Eliza Dolittle transformation, Heston enters.

He’s undoubtedly the most famous person in the room; he’s the reason we are all here and despite all that he’s the most down-to-earth chap I think I’ve ever met. He stands at the end of the table and chats to us while we chomp our way through succulent char-grilled steak, fish and chips that come with its own perfume and the oh-so-fantastic braised ox cheeks. “They’re amazing aren’t they?” agrees Heston, “the texture of them…” and we all go, “Mmmmmm,” in delicious accord. “I’ve ordered you the new Olympic Breakfast so you can try it out,” he tells us. “Any chance of a beer?” another journalist asks. “Sure thing,” says Heston and makes it happen. It feels like I’ve know him for ages. We have a good 30 minutes with the man of the hour, which is almost unheard of with celebrity chefs who are always frightfully busy and being moved on to their next engagement by their clockwatching PRs.

After dinner I pop over to see what the celebrities thought of their dinner. They’re a little uncertain at the intrusion into their inner sanctum but I’ve been chatting with Heston – his aura is upon me. I’m basically one of them now. “I had a burger and one of the fried eggs from the breakfast,” says Kevin McCloud. “It was a really good egg. I put one in my burger.” The sticky toffee pudding and chocolate pudding were also hits on the celeb table but not the banoffee pie: “It tasted mass produced,” says Jan Ravens (from Dead Ringers). “Everything else tasted home cooked.”

As the chatter dies down and the cars start arriving, it’s time for the weary celebs to head home to bed. Or to a glamorous showbiz party. The party, probably. With stars in my eyes I head back to the coach. On my way out I walk past Heston, amongst a crowd of admirers. He excuses himself and comes over. “Thank you so much for coming,” he says, “I really appreciate it.”

What a thoroughly lovely man.

Catch up on the happenings in Big Chef Takes on Little Chef.