The hospital treating Prince William\'s pregnant wife Catherine for severe morning sickness admitted on Wednesday that it fell victim to a hoax call from an Australian radio station. Presenters from Sydney\'s 2Day FM station, posing as Queen Elizabeth II and William\'s father Prince Charles, managed to get through to a nurse who gave an update on Kate\'s status, saying she had not experienced any recent \"retching.\" The private King Edward VII\'s Hospital in London, where 30-year-old Kate was admitted on Monday, confirmed that a nurse discussed Kate\'s condition and said it \"deeply regrets\" the incident, which happened in the early hours of Tuesday. The hoax is deeply embarrassing for the hospital, which has also treated the queen, her husband Prince Philip and Charles\' wife Camilla over the years. Queen Elizabeth is its patron. Hospital\'s chief executive John Lofthous said, \"This was a foolish prank call that we all deplore. We take patient confidentiality extremely seriously and we are now reviewing our telephone protocols.\" 2Day FM presenter Mel Greig, impersonating the 86-year-old monarch, dialled the hospital and asked the operator: \"Could I please speak to Kate, please, my grand-daughter.\" The operator replied: \"Oh yes, just hold on, Ma\'am.\" The call was put on hold and Greig\'s co-presenter Michael Christian asked incredulously: \"Are they putting us through? If this has worked, it\'s the easiest prank call we\'ve ever made. Your accent sucked, by the way.\" Greig was put through to a ward where a nurse told her that Kate was \"sleeping at the moment and she has had an uneventful night\". The nurse added: \"She\'s been given some fluids to rehydrate her because she was quite dehydrated when she came in. But she\'s stable at the moment.\" Greig replied, \"Oh well, I\'ll just feed my little corgis, then,\" while two of her colleagues made barking noises in an impression of the queen\'s corgi dogs. \"So, when is a good time to come and visit her?\" Greig went on. \"Because I\'m the queen so I need a lift down there.\" She then asked Christian, posing as 64-year-old Charles, when he could take her to the hospital. The nurse suggested any time after 9:00 am would be all right, after Kate had \"freshened up\". \"She hasn\'t had any retching with me since I\'ve been on duty and she has been sleeping on and off,\" she added. A spokesman from William and Kate\'s St James\'s Palace office declined to comment. Meanwhile William, second in line to the throne behind Charles, was back at his wife\'s bedside on for a third day. Casually dressed in beige corduroy trousers and a blue sweater, he entered the hospital without acknowledging the international media camped outside the building. Kate is suffering from hyperemesis gravidarum, a severe form of morning sickness that affects about one in 200 pregnant women. News of her pregnancy has ended feverish speculation about a new royal heir that began immediately after the couple\'s lavish wedding in April 2011. The baby will be third in line to the throne. If the child is a girl she cannot be leap-frogged in the line of succession by a future younger brother, following an historic agreement among Commonwealth realms reached in October 2011 that would end male primogeniture. Prime Minister David Cameron confirmed in parliament Wednesday that the changes would apply from the agreement date, so if the legislation does not go through before Kate gives birth, \"there wouldn\'t be a problem.\" It is not the first time that the royal family have been targeted by hoax callers. In 1995 Canadian DJ Pierre Brassard, posing as then Canadian prime minister Jean Chretien, was put through to the queen. The pair spoke for around 15 minutes and Brassard even managed to elicit a promise that the queen would try to influence Quebec\'s referendum on proposals to break away from Canada.