Waitrose’s debut ad starring celebrity chefs Delia Smith and Heston Blumenthal will break at lunchtime on Sunday.

The 20-second ad, styled like a film trailer, will be the first time the two food icons have been seen together on TV. It will be an ad for the real ad, due to debut on March 25.

The ad on Thursday is three and a half minutes long, taking up the whole of the Coronation Street break. It will be a mini cookery programme using seasonal ingredients, showing Heston telling the story of a meat-based dish and giving tips for cookery perfection. Delia will then take over in her classic style, demonstrating each step of how to cook a dessert.

Following the first ad, customers will be able to go into Waitrose to pick up a recipe card for the dish Delia demonstrated. There will also be special offers on key ingredients.

The TV ads will be followed by a series of shorter ads, press ads and some new customer publications.

The new publications are Waitrose Weekend, a guide on what to eat and cook each weekend, plus Waitrose Food Illustrated has evolved into Waitrose Kitchen. The launch issue hits stores on March 25 and features a joint interview with Heston and Delia.