The date is her real birthday – she was born on 21 April 1926 – rather than the official ceremonial birthday in the summer, and it is normally an occasion for a private family gathering rather than large-scale public events.
But this year, Her Majesty is still mourning the passing of the Duke of Edinburgh, just days after she had to sit alone at his funeral, and coronavirus restrictions continue to impact any plans that can be made – in private or public.
So what is the Queen expected to do on Wednesday, and what does she normally do to mark her birthday as the sovereign?
What does the Queen do on her birthday?
The Queen normally celebrates her April birthday in private with her family, according to the royal family website.
Normally the only public acknowledgement of the Queen’s April birthday is a gun salute at midday in central London (a 41 gun salute in Hyde Park, a 21 gun salute in Windsor Great Park and a 62 gun salute at the Tower of London).
This is apart from in 2006, when the Queen celebrated her 80th birthday with a walkabout on the streets of Windsor to meet well-wishers, according to the royal website.
Despite not being a crowd-gathering event like the Trooping of the Colour in June, the gun salute was cancelled in 2020 due to the pandemic, and is reportedly not going ahead again this year in recognition of the period of mourning for Prince Philip.
Her Majesty’s official period of mourning will continue to 23 April, two weeks after his death.
Does the Queen have any birthday traditions?
Former royal chef Darren McGrady, who worked for Princess Diana and Her Majesty, wrote that behind closed doors the private plans are normally marked with a chocolate birthday cake – a recipe that has been passed down through generations of royals.
Mr McGrady said: “The royals have a family birthday cake recipe that dates back to Queen Victoria and written by her chef Gabriel Tschumi who rattled pans in the royal kitchens as long ago as 1899.
“It’s a recipe that I fine tuned for Queen Elizabeth II and made for her twice a year because Her Majesty has an official birthday in June and real birthday in April each year.”
Mr McGrady said it was not just the Queen who enjoyed the chocolate cake but all members of the family requested the cake known as “The chocolate birthday cake”.
“And every cake looks the same because the pastry chefs are instructed never to write a name on the cake just ‘Happy Birthday’. Never Happy Birthday Your Majesty or even Happy Birthday Queenie!”
What will the Queen do to celebrate this year?
Her Majesty has been in residence at Windsor Castle since Christmas – when the royal festivities with other households at the Sandringham estate were cancelled because of the lockdown measures.
It is not known who will join the Queen – if anyone, because of Covid restrictions – on Wednesday.
It was reported that her grandson Prince Harry could remain in the UK to see in the date, before returning to his wife Meghan Markle in Los Angeles, but this has not been confirmed.
Why does the Queen have two birthdays?
According to the royal family website, the monarch has had two birthdays for generations – namely because it is more convenient to have public celebrations in the middle of summer than the darkness of winter if this is when a sovereign’s real birthday falls.
It says: “Official celebrations to mark the sovereign’s birthday have often been held on a day other than the actual birthday, particularly when the actual birthday has not been in the summer.
“King Edward VII, for example, was born on 9 November, but his official birthday was marked throughout his reign in May or June when there was a greater likelihood of good weather for the Birthday Parade, also known as Trooping the Colour.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies