Grocery and general merchandise giant Asda will become one of the first retailers – and maybe the first – to sell royal wedding merchandise when a £5 mug goes on sale tomorrow.

Asda will sell the mugs, which commemorate the engagement today of Prince William and Kate Middleton, online and in its photocentres in shops.

A spokeswoman for the retailer said the royal wedding could prompt “hysteria similar to when Charles and Di wed in the 1980s”. The mug was designed earlier this year.

She said: “Royal crockery is good British tradition. Kate and Wills are the nation’s sweethearts and our shoppers have said they should love to be able to buy a piece of history while doing their weekly shop. Nothing says congratulations like your face on a mug.”