St George's Square was transformed into a winter wonderland for the Sainsbury's advert, with a 20ft Christmas tree, strings of lights and a snow machine that showered the crowd that had gathered to catch a glimpse of the star. Hundreds of fans clamoured for autographs and photos of the chef, who happily obliged during breaks from shooting, and scores more lined up to bag a part as an extra in the advert, which was shot by Full Monty director Peter Cattaneo.

Jamie was filmed whipping up smoked salmon crostinis from a trailer in front of the Shoulder of Mutton pub.

Licensee Holly Burnett said: "It's all I have heard about all week and we've been very very busy today."

Other businesses welcomed the media frenzy, including Moyles hotel, where the chef tucked into Yorkshire fare the night before.

Head chef Mark Brankin said: "He really enjoyed our black pudding. It was good meeting him, he was a nice bloke. It was his first time here and he didn't seem to know where he was – he asked if we were near Rotherham!"

A Sainsbury's spokeswoman said: "The cast and crew have been made to feel extremely welcome."

The advert is expected to hit screens in November.