Prince Harry and Meghan Markle were due to attend the WellChild Awards in London yesterday evening, but cancelled their plans after news of the Queen's poor health emerged.
Just after 12.30pm on Thursday, Buckingham Palace issued a rare statement saying that doctors were concerned about the monarch's health, but that she remained "comfortable" at Balmoral.
The announcement prompted a number of senior royals to travel to Scotland to be with Queen Elizabeth II.