That means that the Diana storyline will be in the fourth season, in as early as the first episode. And the show has already set the stage for her arrival — first by having Prince Charles and Camilla Parker Bowles (née Shand) meet and fall in love, and then by having Camilla acquiesce to marry Andrew Parker Bowles instead. This left Prince Charles heartbroken and tasked with finding a new future queen to be by his side. We know that search will eventually lead him to Lady Diana Spencer and, later down the road, back to Camilla.