The monarch is determined to partake in his official birthday celebrations on June 15, with Buckingham Palace and the Ministry of Defence exploring options to ensure his participation without jeopardizing his health.
Measures being considered include observing the military parade from a podium instead of on horseback and traveling from Buckingham Palace in a carriage.
Despite medical advice to avoid large public gatherings during his cancer treatment, the King has maintained his office duties and limited public appearances since his diagnosis in January.
Traditionally, the monarch rides down the Mall to Horse Guards Parade during Trooping the Colour, inspects the troops, and returns to Buckingham Palace for a balcony appearance during an RAF flypast.
Contingency plans, similar to those implemented for Queen Elizabeth II when she could no longer ride on horseback, are being reviewed by palace officials for this year's event.
In previous years during the pandemic, the late Queen's official birthday was commemorated with scaled-back events at Windsor Castle, and in 2022, Prince Charles took part in Trooping the Colour on behalf of his mother for the first time.
Decisions regarding the King's participation in this year's event will be dependent on his health and medical advice closer to the date.
The Princess of Wales is scheduled to lead the Colonel's Review before Trooping the Colour this year as the Colonel of the Irish Guards.
Confusion arose when the Ministry of Defence began ticket sales for the event, prematurely announcing the Princess's participation in the review and the King's presence at Trooping the Colour, prompting clarification from Kensington Palace.
Additionally, the Princess underwent abdominal surgery in January and is currently recuperating at home, with plans to resume public engagements after Easter if her health permits.
Recent sightings of her shopping at a Windsor farm shop with Prince William and attending her children's school sports matches have sparked optimism about her recovery.