LONDON  -- Prince William will replace his wife Kate on this weekend's official visit to Malta because the pregnant Duchess of Cambridge is still suffering from acute morning sickness.

Palace officials said Thursday the decision to cancel what would have been Kate's first official solo voyage overseas was made in consultation with her doctors.

The palace said William will instead represent his grandmother, Queen Elizabeth II, at the commemoration of the 50th anniversary of Malta's independence.

The duchess is in the first 12 weeks of her second pregnancy. She has suffered acute morning sickness during the early phases of both pregnancies and has curtailed her royal engagements in the past two weeks.