Since the start of the twenty-first century King Harald has been unable to perform his duties as sovereign due to ill health on a few occasions: from December 2003 to mid-April 2004 due to urinary bladder cancer, from April to early June 2005 due to aortic stenosis, and in 2020 he was in hospital for cardiac surgery (replacement of a heart valve). Crown Prince Haakon served as the country's regent on these occasions, including giving the King's Speech at the State opening of parliament in 2020.