Queen Elizabeth will be absent from the royal Garden Parties this year.
The 96-year-old monarch - who has been struggling with her mobility and recently had a bout of COVID-19 that left her "very tired and exhausted" - will be replaced by other members of the British royal family, who will be announced in "due course", when the annual parties return to the royal residence for the first time since 2019 next week.
A spokesman said: "Her Majesty the Queen will be represented by other members of the royal family at this year's garden parties, with details on attendance to be confirmed in due course."
The first garden parties take place on May 11, 18 and 25 at Buckingham Palace, while The Holyroodhouse party in Edinburgh, Scotland, is set for June 29.
The queen's daughter, Princess Anne, is already hosting the Not Forgotten Association Annual Garden Party on May 12, as she is a patron of the charity.
Each year, the royal is joined by more than 30,000 guests to enjoy the picturesque gardens at Buckingham Palace as thanks for their contributions to the community and spends a lot of time on her feet greeting them.
Elizabeth has been using a walking stick at various engagements, but she was without the aid when she met the president of Switzerland last month.
The royal was seen standing unassisted as she shook hands and posed for photographs with Ignazio Cassis and his wife Paola in the Oak Room at Windsor Castle.
The engagement was the queen's first since she returned to Windsor following a week-long break at her Sandringham estate in Norfolk.
Meanwhile, it was recently revealed that Her Majesty had taken delivery of a state-of-the-art golf buggy to help her move around in comfort.
The 43 mph four-seater electric cart was built by Danish firm Garia as part of a tie-up with Mercedes-Benz and is described as putting “many passenger cars to shame”.
It has a range of 50 miles before its battery needs recharging and while she's relaxing on one of the four brown leather seats, the queen can tuck into treats from its fridge, or check for weather updates and mapping on the tablet-style 10in screen next to the steering wheel.
The buggy has "weather enclosure" doors and windows, so the monarch will be able to use it all-year round, and it also has headlights, 14in alloy wheels, a lockable boot, heated windscreen, cup holders and even Bluetooth speakers.
A source said: "The cart is a new addition to the castle, and they all think it’s a great idea. It’s certainly fit for a Queen and hopefully it will help her fulfil her engagements.
“Everyone wants her to carry on for as long as possible being seen by the public.
“I’m sure the Queen would rather walk to events and carry on as normal, but she is struggling at the moment."