Waitrose makes celebrity chefs a key ingredient

The two chefs will appear together in the supermarket's first personality-fronted ads which will appear on television, in the Press and online towards the end of March.

Waitrose said Smith and Blumenthal would act as "food ambassadors" for the brand, sharing tips and recipes and discussing ingredients.

Smith, whose latest title How to Cheat at Cooking became the fastest selling cookery book of all time, said of her new role: "After many years of communicating recipes I am delighted that now everyone who follows them will be absolutely certain of being able to find all the ingredients."

Self-taught chef Blumenthal has achieved international acclaim with dishes including snail porridge and sardine-on-toast sorbet since he opened his Fat Duck restaurant in Bray, Berkshire in 1995.

Waitrose director of marketing Rupert Thomas said: "Delia and Heston embody the Waitrose passion for food and, with them, we aim to get the nation cooking, experimenting and enjoying food."