When princesses and pop stars want a statement-making hat they turn to their favorite milliner: Philip Treacy (shown with Kate Winslet). Recently, his fanciful creations graced the heads of Sarah Jessica Parker, Serena Williams, and 37 members of the Royal Wedding party. So who is Mr. Treacy? The Irish-born designer has been creating toppers since the age of five, when he made miniature hats for his sisters' dolls, and he later honed his sewing skills at Dublin's National College of Art and Design and London's Royal College of Art. Just before his graduation, Treacy showed his hats to Tatler fashion director Isabella Blow, who took the young designer under her wing. Treacy opened up shop in the basement of Blow's London home, and eventually scored jobs designing hats for Chanel, Alexander McQueen, Ralph Lauren, and more. The five-time British Accessory Designer of the Year award winner has a loyal following: Lady Gaga, Demi Moore, and the British royal family are some of his best clients. Click through the gallery to see some of Treacy's most famous toppers!