Duchess of Cambridge leaves hospital after bout of sickness Prince WiIliam, the Duke of Cambridge, and Catherine, the Duchess of Cambridge, leave the King Edward VII hospital in London. Photograph: Leon Neal/AFP/Getty Images With a smile and a wave the Duchess of Cambridge left hospital on Thursday to the undoubted relief of her husband and also of the international news crews camped outside in the bitter cold throughout her three-night stay. She emerged from the King Edward VII private hospital in central London looking relaxed after receiving treatment for hyperemesis gravidarum, an acute form of morning sickness. As journalists shouted to inquire how she was feeling, she replied "much better" as she briefly posed on the hospital steps for a photograph with Prince William, 30, at her side. The duchess, 30, who is less than 12 weeks pregnant, will now rest at the couple's London home in Kensington Palace. She was admitted to hospital on Monday afternoon after becoming unwell at her parents' Berkshire home. Just hours after her admission, two Australian radio DJs impersonating the Queen and Prince of Wales duped hospital staff into divulging intimate medical details. The embarrassed hospital has condemned the hoax as "pretty deplorable" and "journalistic trickery." But Prince Charles seemed to make light of the prank at an engagement at HMS Belfast on Thursday. "How do you know I'm not a radio station?" he joked to reporters. Asked about the prospect of becoming a grandfather, he said: "I'm thrilled, marvellous. It's a very nice thought to become a grandfather in my old age. He added: "I'm very glad my daughter-in-law is getting better, thank goodness." The duchess has pulled out of her two planned royal engagements this weekend - a Centrepoint Royal Albert Hall fundraiser and the British Military Tournament. William is due to attend them without her. The couple's diary also includes the London premiere of The Hobbit film on Wednesday, but it is not yet clear whether Kate will be well enough to attend.