The Duchess, who is pregnant with her second child, has been suffering from Hyperemesis Gravidarum, and has cancelled the visit due to ill health.
''Her Royal Highness continues to suffer from the effects of Hyperemesis Gravidarum. The decision not to travel was taken by the Duke and Duchess on the advice of the Duchess's doctors.
'The Duke is honoured to represent Her Majesty The Queen on the visit, which commemorates the 50th anniversary of Malta's independence.
''The visit itinerary remains unchanged.''
Source : Daily Telegraph.co.uk