Two Australian radio DJ's made a prank call to the hospital where Prince William's pregnant wife, Kate Middleton, is staying with acute morning sickness.

The pair, claiming to be Queen Elizabeth II and her son, Prince Charles, got through to Kate's private nurse at the hospital.

They had a brief conversation that included some details of her condition.

The hospital says it deeply regrets the incident, it takes patient confidentiality very seriously and is reviewing its telephone protocols.

And the radio show has posted an apology for the call on its official Twitter feed.