The Princess Switch 3: Romancing the Star

Princess Stacy Wyndham of Belgravia and Lady Margaret Delacourt, Queen of Montenaro, reunite to host a traditional Christmas festival in Montenaro, during which the Vatican loans the Queen one of their most priceless treasures, the Star of Peace, for display. Unfortunately, before the festival concludes, the Star is stolen and the police have no leads. To prevent a diplomatic crisis, Stacy and Margaret turn to their old nemesis, Lady Fiona Pembroke, for help, and before long, they discover that the Star is being held in the collection of a wealthy, corrupt businessman. With the help of Fiona's criminal ex, Peter, the girls must stage an elaborate heist to regain the Star - which includes both Stacy and Margaret impersonating Fiona.