Queen Elizabeth's diary will be covered by seven other members of the royal family "for as long as is needed".
The 95-year-old monarch has been resting at Windsor Castle for the last month and was forced to pull out of the Remembrance Sunday service at the Cenotaph over the weekend after suffering an "unfortunate" back strain.
Royal officials are said to be taking a "cautious approach" to the queen's engagements in the near future, with no public meetings expected for the rest of the year, and they warned there should be a "realistic expectation" that the sovereign's commitments will be dramatically scaled back over the winter months.
Instead, Prince Charles, his wife Camilla, the Duchess of Cornwall, and his son and daughter-in-law, the Duke and Duchess of Cambridge, as well as the queen's daughter Princess Anne, her youngest son Prince Edward, and his wife Sophie, Countess of Wessex, are expected to step in and cover many of the engagements.
A source told the Daily Mirror newspaper: “The queen remains as sharp as a pin, but the reality is she needs to take a period of rest following an extremely busy start to normal duties after the coronavirus restrictions were lifted.
“The senior members of the family are all aligned in that they will be available to help out wherever they can and for as long as is needed.”
The queen is said to be "hugely comforted" to know the rest of the family are ready to step in to her duties.
A source said: "The queen has been and continues to be hugely comforted by many of her family rallying round this year and will no doubt be looking forward to being together for Christmas this year.”
A royal spokesperson confirmed the queen would continue to undertake “light duties” while recovering from her back injury and she is scheduled to undertake some virtual engagements in a few days time.
For the first time in the General Synod's 51-year history, the queen will not be there for her five-yearly visit to the Church's national assembly - which she attends in her capacity as Supreme Governor of the Church of England - on Tuesday (17.11.21) as originally planned.
Charles, Anne, and Prince William have in recent terms taken on investiture duties on behalf of the queen, and apart from awarding late war hero Sir Captain Tom Moore his knighthood last summer, the last investiture ceremony the monarch was part of was in November 2019.