Celebrity Parents Marie-Chantal of Greece helps launch the Walton Street Christmas Party By Staff Author Published on December 5, 2007 11:30 AM Share Tweet Pin Email Marie-Chantal, Crown Princess of Greece, 39, helped to launch the Walton Street Christmas Party in Knightsbridge on Monday. She was assisted by daughter, Princess Maria-Olympia, 11, and sons Prince Constantine Alexios, 9, Prince Achileas-Andreas, 7, and Prince Odysseas-Kimon, 3. Father is Crown Prince Pavlos of Greece, 40. Source: Hello! Thanks to CBB reader Mary Beth.