Kate Middleton, who's still receiving cancer treatment, is said to be very determined and desperate to attend the upcoming royal event with her husband Prince William and their children.
The Princess of Wales, who's been out of sight since she announced her caner diagnosis in March, is eager to make a balcony appearance for Trooping the Colour in London on June 15.
However, King Charles and William, according to an insider, "are not impressed with the idea.
"William and King won't allow Catherine to return to the royal duties until her medical team gives Kate all-clear as she still continues her treatment."
"King Charles and William don't want Kate to take any risk as they are taking all necessary steps to ensure that the mother-of-three makes a smooth recovery," the source added.
They continued: "Kate Middleton is thankful for the time she's spending at home while focusing on her health, but very excited to attend the event that she and her kids eagerly await for almost a year.
On the other hand, Buckingham Palace has also not revealed the details about Trooping the Colour, which is a ceremonial event performed every year on Horse Guards Parade in London to celebrate the official birthday of the British sovereign. It is also known as the Sovereign's Birthday Parade.
Speculations are rife when the future Queen returns to royal duties. William, according to reports, has directed the Kensington Palace to maintain privacy protocols around Kate as his top priority is her health.
Last year, King Charles took the royal salute and inspected the troops at Horse Guard's Parade before returning to Buckingham Palace to watch a flypast.
Queen Camilla, Prince William, Kate Middleton and their three children Prince George, Princess Charlotte and Prince Louis joined King Charles for the photo op of the day on the palace's balcony.