Description:The Queen, accompanied by Catherine, the Duchess of Cambridge and Camilla, the Duchess of Cornwall went shopping at one of London's most luxury food halls, Fortnum and Mason, on Thursday. It was the first time that the trio have been on an official engagement together, apart from events such as the royal wedding, Trooping the Color and Christmas church services. Kate was shown Fortnum's famous specialty teas and the Queen inspected honey and preserves and unveiled two plaques.(2:50)