The Buckingham Palace on Thursday informed that Queen Elizabeth II is under medical supervision after doctors expressed their concern over her healthy condition.
In an official statement, the Buckingham Palace said, "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," the statement added.
The newly elected United Kingdom Prime Minister, Liz Truss said that the whole country will be "deeply concerned by the news from Buckingham Palace this lunchtime."
Taking to Twitter, UK PM said, "The whole country will be deeply concerned by the news from Buckingham Palace this lunchtime. My thoughts - and the thoughts of people across our United Kingdom - are with Her Majesty The Queen and her family at this time."
The announcement comes after the Queen, postponed the key meeting on Wednesday after the doctors advised her to take a rest.
Queen, 96, was scheduled to attend a virtual meeting of her Privy Council, a day after Liz Truss was appointed as the new UK Prime Minister.
The Privy Council is a body formed of senior politicians who act as the Queen's official advisers. During the gathering on Wednesday, Truss would have taken her oath and new cabinet ministers would have been sworn into their roles.
"After a full day yesterday, Her Majesty has this afternoon accepted doctors' advice to rest. This means that the Privy Council meeting that had been due to take place this evening will be rearranged," a Palace spokesman was quoted as saying.
The Queen is currently at Balmoral Castle, her Scottish country residence, where she received Truss and her predecessor Boris Johnson on Tuesday.
"The Queen received Liz Truss at Balmoral Castle today. Her Majesty asked her to form a new Administration. Ms. Truss accepted Her Majesty's offer and was appointed Prime Minister and First Lord of the Treasury," The Royal Family tweeted.