Queen Elizabeth is expected to spend her 96th birthday (21.04.22) at Sandringham.
The British monarch - who has been struggling with poor mobility in recent months - is said to have chosen to spend the occasion at the royal family's Norfolk estate to feel closer to her late husband, Prince Philip.
A source told the Daily Mirror: "The Queen decided very recently that on her birthday she wanted to be as close as possible to her late husband and in an environment that was very close to both of their hearts. Sandringham holds so many special memories for the Queen and Prince Philip as well as the rest of the royal family."
The queen will be staying at Wood Farm, where Philip - who died last April, aged 99 - lived following his retirement in 2017.
Members of the family will pop in to spend time with the royal during her stay.
Ahead of her birthday, the royal had a special visit from The Duke and Duchess of Sussex at Windsor Castle.
The queen's grandson and his wife popped in to see Prince Harry's grandmother before heading to the Netherlands for the Invictus Games, and the monarch gave him some words of support for the athletes taking part.
Speaking to the BBC, Harry said: "She had plenty of messages for Team UK which I've already passed on to most of them.
"So, it was great to see her and I'm sure she would love to be here if she could."
The visit marked the duchess' first trip to the UK since 2020, while the duke is thought to have last visited the UK in July.
Harry was a high-profile absentee from a memorial service for his grandfather, the Duke of Edinburgh, in London in March.
The royal couple - who are now based in the US, after tying the knot in 2018 - stepped down as senior members of the royal family in January 2020.
And the 37-year-old royal previously claimed he was unable to return to the UK amid concerns over security arrangements for his family.