His visit is part of the one-off, month-long Season of Celebrations - opening on Monday - to launch the newly-expanded store. And, in a series of seminars and demonstrations which cover most Fortnum products from furniture to aromatherapy; food, chefs and eating play a significant part.
There are foodies representing most parts of Britain, followed by taster lunches. BBC cook, Michael Barry, looks at food from the South East; chef, Peter Jackson, gives "A Taste of Wales"; and there are seminars on the Scottish larder, caviar tasting, honeys, whiskies and practical tips from Sybil Kapoor, followed by lunch based on recipes from her new Simply British cookbook. Whatever whets your appetite.
"We want to highlight that good foods come from Britain, not just France and the Far East," a spokeswoman says. "Our food halls specialise in British food and we have a whole host of different foods from around it. But, we also want to create awareness of our non-food areas and are holding demonstrations in departments throughout the store."
Specialists are coming in from a range of Fortnum suppliers. For example, William Yeoward, of the eponymous crystal makers, will be autographing pieces of his crystal while The Riedel Glass Challenge gives the low-down on these special wine glasses, designed with a particular shape and glass to restrict air into the wine and improve its taste.
Other demonstrations - most of which take place in the new Burlington Room - include meeting the expert on Steiff Teddy Bears, a book signing by florist Kenneth Turner, meeting the designer Sarah Barton-King of Orford & Swan Silk Scarves and Lorenzo Villoresi, creator of the men's fragrance range. Honey-maker Murray McGregor gives a guide to honeys of the world, including the rare French Wild Mountain Rhododendron while aromatherapy houses discuss body treatments and offer head massages. Fashion shows also are taking place in the fashion departments.
The choice is large and varied, and will provide interesting vignettes for ladies and gentlemen with time for a leisurely lunch.
Season of Celebrations, Fortnum and Mason, 181 Piccadilly, London W1 (0845-300 1707), 21 Sept to 17 Oct