Princess Marie-Chantal marked her husband Crown Prince Pavlos’ 57th birthday on Monday, celebrating with their children with a low-key party held at what looks to be Princess Olympia’s chic Notting Hill apartment Princess Marie-Chantal marked her husband Crown Prince Pavlos’ 57th birthday on Monday, celebrating with their children with a low-key party held at what looks to be Princess Olympia’s chic Notting Hill apartment