Call it tea with Kate and the in-laws.
The Duchess Of Cambridge will join her grandmother-in-law, Queen Elizabeth, and her mother-in-law, Camilla, the Duchess of Cornwall, at an official engagement at Piccadilly's flagship Fortnum and Mason's store on March 1, as "three royal ladies have tea," a royal source tells PEOPLE. The tea party with the trio will serve as the centerpiece of an event to mark the regeneration of the London area ...