The Queen will not be attending the Epsom Derby tomorrow, and instead will send Princess Anne in her place.
The Queen had been due to attend the derby, but has been forced to pull out because of mobility issues.
It comes during her Platinum Jubilee weekend which has seen the country turn out to celebrate 70 years of her reign.
However, this year has seen continuing concerns about the monarch's health and this marks the second jubilee event the 96-year-old has been forced to miss.
She had previously missed the thanksgiving service at St Paul's today, but appeared twice during Thursday's celebrations.
Keep up with the latest jubilee news with The Mirror's live blog here.
There had been speculation the Queen would not appear at the race due to her ongoing mobility issues and she is now expected to watch the event from Windsor Castle. Princess Anne will go in her place.
It is believed Her Majesty is continuing to rest after suffering discomfort from standing for long periods at Trooping the Colour on Thursday
The Queen reportedly had a "lovely time" during Thursday's celebration but found the day "very tiring", the Duchess of Cambridge is said to have told an attendee at the Guildhall reception on Friday.
Sky News reported that Gill Smallwood, from Bolton, a chief executive of a domestic violence charity, spoke with Kate after a service of thanksgiving at St Paul's Cathedral.
Ms Smallwood said she asked Kate how the Queen was doing and said Kate told her the Queen "was fine, it was just very tiring yesterday, and she (the Queen) had had a lovely, lovely time"
However, the Queen's withdrawal from Epsom today will come as a bitter blow to the monarch.
Her love of horses is well known - and Duchess of Cornwall Camilla Parker Bowles said she has an "encyclopaedic Knowledge" of racing.
“I think this is her passion in life, and she loves it and you can tell how much she loves it,” Camilla said in an interview with ITV.
“She can tell you every horse she’s bred and owned, from the very beginning, she doesn’t forget anything. I can hardly remember what I bred a year ago, so she’s encyclopaedic about her knowledge.”
The Queen has only missed the Derby on four occasions in the past 75 years, and had had three of her best horses put forward to compete this weekend.
Last month one of her horses, a three-year-old colt called Reach For The Moon, was ruled out of her favourite race.
The derby coincides with Lilibet, her great-grandchild's, first birthday. Harry and Meghan and their children travelled over from California for the Queen's jubilee weekend.
On Thursday, the Queen beamed during the RAF fly past which saw 71 aircraft, including Red Arrows, put on an amazing display over London.
She was accompanied by her immediate family with Prince Andrew, Prince Harry and Meghan the only noticeable absences.
The monarch first appeared on the balcony of Buckingham Palace on Thursday as she waved to thousands of Brits before she was joined by the Duke of Kent as they took the salute during Trooping the Colour.
Half an hour later she reappeared with other senior royals for the RAF fly past and she also attended a beacon lighting event on Thursday night.
Phil White, London Regional Director for The Jockey Club, said: “We would like to wish Her Majesty The Queen a wonderful Platinum Jubilee. It is a rare occasion that The Queen is unable to join us at Epsom Downs but we are delighted she plans to enjoy Derby Day on television.
“We have big plans to celebrate Her Majesty’s contribution to horseracing and the nation, and these will continue in full tomorrow.
"The Derby is a unique race and we are looking forward to welcoming people in their thousands to help us create a spectacular carnival atmosphere.”
