Donny Osmond has apologised to U.S. TV talk show host Larry King after criticising him for revealing live on air that his sister MARIE's son, MICHAEL, was in rehab. King blurted out the news during an Osmonds special on 14 November (07), leaving Marie struggling to fight back tears as her brother helped comfort her. Marie told King, "My son was put into a rehab... My son is amazing... He is the most amazing kid." At the time, Donny insisted King's line of questioning which led to the revelation was unfair - but he has now retracted his comments after learning the story was about to be broken by U.S. tabloids. He says, "I was very upset about it. I thought it was very unfair for Larry King to throw that question at Marie the way he did. "(But) I have to back up and apologise publicly to Larry King because I came out and said some things against him. In hindsight, Larry King did Marie a favour. She was able to make a statement about the situation. ... And so she's grateful to Larry." Marie, who has eight children, has not disclosed where 16-year-old Michael is being treated or the nature of his problem.