Saturday marks the third day of Platinum Jubilee celebrations, with the Queen no longer attending the Epsom Derby.
Missing her second event of the bank holiday weekend, the monarch will watch the Derby on television instead, Buckingham Palace said.
She will be missing the Derby for just the third time in a 70-year reign.
The Queen has experienced mobility problems in recent weeks and did not attend Friday’s Jubilee thanksgiving service at St. Paul’s Cathedral.
This came after she experienced “discomfort” at events on Thursday.
In her place, the Princess Royal will represent the Queen at the horse race in Surrey.
The Prince of Wales and Duke of Cambridge are set to make tributes to the Queen at an open-air concert on Saturday evening.
Members of the royal family will also be travelling to different nations, with Prince William visiting Cardiff and Prince Edward in Northern Ireland.
There will be a special Jubilee concert hosted outside Buckingham Palace, called Party at the Palace, with a live audience of some 22,000 attendees.
William and Charles will address the crowds at the end of the two-and-half-hour event, which will be broadcast by the BBC.
The star studded concert includes performances from Diana Ross, Queen + Adam Lambert, Alicia Keys, Hans Zimmer and George Ezra.
There will also be appearances from Sir David Attenborough, David Beckham and Stephen Fry, alongside a recorded performance from Sir Elton John.