Queen Elizabeth II will not attend the Jubilee service at St Paul's Cathedral on Friday, 3 June, due to some discomfort that she experienced while watching the parade at Buckingham Palace on Thursday, 2 June, the BBC reported.
According to a statement by the Palace, the decision was made with "great reluctance" after taking into account the "journey and activity required."
She did, however, take part in a beacon lighting ceremony on Thursday evening.
The Palace statement added that she "would like to thank all those who made today such a memorable occasion."
The next celebratory event that the Queen is due to attend is the Derby at the Epsom racecourse on Saturday, 4 June.
It is still unclear whether she will make an appearance there or not.
What Is the Platinum Jubilee?
On Thursday, Queen Elizabeth II completed 70 years since her coronation as the Queen of the United Kingdom and head of the Commonwealth.
From Thursday to Sunday, the UK government will host events and installations for the British public that will "mix traditional pageantry with cutting edge technological displays" in villages, cities, and towns all over the country, according to Bloomberg.
Millions of British people have geared up for street parties to mark the monarch's 70 years on the throne, over the four-day bank holiday weekend.
The celebrations were kicked off with a parade of thousands of soldiers marching down the Mall in London.
A Royal Air Force (RAF) flypast of 70 aircraft included the Red Arrow display team and the RAF Battle of Britain Memorial Flight, featuring Spitfires and Hurricanes, among other aircraft.
(With inputs from the BBC and Bloomberg.)