The Duchess of Cambridge, 34, has clearly being practicing her curtsies, as she pulled off the move with aplomb as she deferred to the Queen when the monarch left the service of thanksgiving to mark her 90th year at St Paul's Cathedral in London today (left). Before the ceremony the Duchess had a near miss as Prince William alerted her to a grate before she got her high heel caught in it (right). Kate was seen laughing about the potential mishap with Prince Harry (inset) as they made their way to their seats.