In recent months, the Queen has been limiting her attendance at certain events after her doctor advised her to rest following a series of issues with her health.
She has also recently recovered from Covid alongside the Princes of Wales, Charles and wife Camilla, the Duchess of Cornwall.
The Royal Family are due to make an appearance at the Commonwealth service alongside Charles and Camilla and Kate and William - but there will be no sign of the Queen despite her now testing negative for the virus.
This will be the first time in almost a decade that Her Majesty will not be there with Hull Live reporting that she didn't attend in 2013 due to a nasty bout of gastroenteritis.
Before that, the Queen, who is almost 96, had not been absent from a Commonwealth Day observance service for 20 years - the last time being when she had flu in 1993.
The Commonwealth, affectionately known as the "family of nations", has played an important role throughout her reign, and she takes a special interest in the institution.
In a statement, a Buckingham Palace spokesman said: "After discussing the arrangements with the royal household, the Queen has asked the Prince of Wales to represent Her Majesty at the Commonwealth service at Westminster Abbey on Monday.
"The Queen will continue with other planned engagements, including in-person audiences, in the week ahead."
Highlights of the service at Westminster Abbey on Monday will include an address by former archbishop Lord Sentamu, a reflection by young Tongan leader Elizabeth Kite and special musical performances from Emeli Sande and Mica Paris.
Organised by the Royal Commonwealth Society, the service will feature the Queen’s Commonwealth Day message.
