All of the Queen's children are now with her as she receives "medical supervision" at Balmoral.
The news comes after Buckingham Palace announced that Her Majesty's doctors had become "concerned" for her health.
Shortly after midday on Thursday, September 8, the Palace shared the following statement:
"Following further evaluation this morning, The Queen’s doctors are concerned for Her Majesty’s health and have recommended she remain under medical supervision.
"The Queen remains comfortable and at Balmoral."
Following the news, BBC News reported that members of the Queen's family had been informed and were traveling to Balmoral to be by her side.
The Queen's daughter, Princess Anne was already in Scotland undertaking royal engagements and made her way to Balmoral.
Additionally, The Prince of Wales was also pictured arriving at the royal estate, along with his wife, Camilla, the Duchess of Cornwall.
Other members of the Royal Family arrived at Aberdeen airport this afternoon. As well as the Duke of Cambridge, the Queen's sons the Duke of York and the Earl Wessex were seen disembarking an RAF aircraft and boarding awaiting cars. The Countess of Wessex was also present.
Around one hour later, the motorcade arrived at Balmoral, meaning that all four of the Queen's children are now with her.
A representative for Prince Harry, the Queen's grandson, has confirmed that he is traveling to Balmoral without wife Meghan Markle - who is expected to be staying in London. The couple was due to attend a charity event this evening, but now neither will be attending following today's news about the Queen's health.
Another member of the Royal Family who is unable to attend is the Duchess of Cambridge, who will reportedly be staying in Windsor with the couple's children, who have recently returned to school.
Outside of the gates of Balmoral, reports state that well-wishers have gathered along with members of the media from around the world.
Throughout the day, crowds have gathered outside of Buckingham Palace as the UK awaits an update on the longest reigning monarch in the nation's history.