Article continues below advertisementKing Charles has won high praise for his high-profile U.S. state visit - as sources tell OK! it was his estranged son Prince Harry's "worst nightmare" amid ongoing tensions between the monarch and the duke.The 77-year-old king and his wife, Queen Camilla, 78, concluded their four-day visit to the United States last week, hosted by Donald Trump. Article continues below advertisementSource: MEGAKing Charles concluded his four-day visit to the U.S.