Boris Johnson says he spoke to the Queen this week and she was in “very good shape”, adding that the whole country “wishes her all the best”.
It comes after the 95-year-old monarch was advised by doctors to rest for at least the next fourteen days.
Her Majesty accepted their recommendations that she only undertakes “light, desktop-based tasks” and not to conduct any official visits, Buckingham Palace said Friday.
The decision means she will not be able to attend the Festival of Remembrance at London’s Royal Albert Hall on Saturday 13 November.
However, the palace said she has the “firm intention” of leading the nation in honoring the country’s war dead on Remembrance Sunday the following day.
It is significant that the monarch wishes to attend the ceremony at the Cenotaph at Whitehall, as it is a major event on the calendar of the Sovereign and on which she has placed great emphasis.
The Prime Minister said on Saturday: “I spoke to Her Majesty, as I do every week, this week, and she is in very good shape.
“She just needs to follow the advice of her doctors and get some rest, and I think that’s the important thing. I’m sure the whole country wishes her all the best.”
On Thursday, Buckingham Palace shared footage of Her Majesty presenting David Constantine with the Queen’s Gold Medal for Poetry.
In the short clip, the queen jokes about having to talk to him via video link and says, “I’m very happy to have the chance to see you, albeit mechanically this morning!”
Earlier this week, it was announced that she had withdrawn from personally attending the upcoming COP26 climate summit, which begins in Glasgow this weekend, following a busy schedule recently.
The queen spent Wednesday night last week in the hospital after canceling a visit to Northern Ireland.
She was admitted for “preliminary investigations” but returned to Windsor Castle the next day.
It has not been revealed what medical tests she had at the private King Edward VII Hospital in central London. It was her first overnight stay in the hospital in eight years.
Sky’s Royal Correspondent Rhiannon Mills said Her Majesty’s hospitalization was not related to COVID-19.
In recent days, the Queen completed her first official engagements since her brief hospital stay when she held virtual audiences at Windsor Castle.
She wore a yellow dress and her three-string pearl necklace when she met South Korean ambassador Gunn Kim on Tuesday, and separately Swiss ambassador Markus Leitner.