The Princess of Wales is undergoing treatment for an undisclosed form of cancer.

As the royal family prepares for Trooping the Colour, its heir is determined to put on a united front.

On May 30, Kensington Palace, which handles the office for the Prince and Princess of Wales, confirmed to Fox News Digital that Kate Middleton won’t be serving as Inspecting Officer of the traditional Colonel’s Review on Saturday. Instead, she will continue to focus on her recovery.

The Princess of Wales has been keeping a low profile since she publicly announced her cancer diagnosis in March.

Royal experts told Fox News Digital that Prince William is determined to put on a united front as his wife privately battles cancer. (Max Mumby/Indigo/Getty Images)

“I imagine Prince William has suffered his own private turmoil, having both his father and wife undergoing cancer treatment at the same time, and without the support from his brother, Prince Harry,” British broadcaster and photographer Helena Chard told Fox News Digital.

“It must… be a lonely time,” said Chard. “I know he values every moment he spends with his wife as a doting husband and family man… Both the Prince and Princess of Wales have had time to reflect on life while the princess has been undergoing treatment. They have spent as much time together as possible and, I can imagine, are closer than ever. They have endured a surprising wake-up call and will want to seize each day and live their best lives ever.”

It is understood that the honor will fall to Lieutenant General James Bucknall, KCB, CBE. Kensington Palace hasn’t officially announced whether the princess will attend this year’s Trooping the Colour or not.

Catherine, the Princess of Wales (in her role as Colonel of the Irish Guards) and Prince William, Prince of Wales pose for a regimental photograph as they attend the 2023 St. Patrick’s Day Parade at Mons Barracks in Aldershot, England, on March 17, 2023. (Max Mumby/Indigo/Getty Images)

The Princess of Wales announced she was undergoing treatment for cancer in March and has been out of the public eye since she underwent planned abdominal surgery in January.

“The princess is not expected to return to work until it’s cleared by her medical team. Early childhood will continue to be central to her public work,” a Kensington Palace spokesperson previously told Fox News Digital.

William has since returned to public duties in her place, along with other members of the royal family. Earlier this month, he went on his first overnight trip to visit the Duchy of Cornwall’s housing project focused on helping homelessness.

Prince William and Kate Middleton pose with their children on the Buckingham Palace balcony during Trooping the Colour in London on June 17, 2023. (Chris Jackson/Getty Images)

Many royal watchers are hoping Kate will make a grand appearance at this year’s Trooping the Colour, which is the public celebration of the monarch’s birthday. The festivities take place in June each year, regardless of the monarch’s actual birthday.

“Everyone hopes that the Princess of Wales will show her face at Trooping the Colour and appear on the Buckingham Palace balcony with other members of the royal family,” said Chard. “However, this will depend on how she is feeling and whether her medical team feels she is fit enough. Although the Princess of Wales has turned a corner health-wise, it is highly likely that she will be seen after the summer holidays, autumn time.”

“The Princess of Wales is the most popular member of the royal family,” Chard continued. “She is important to the future of the monarchy. As such, everyone is more interested in her returning to public duties when she is fit and well. Of course, it will be a bonus if she makes a glittering appearance, but it won’t put a damper on the king’s birthday parade if she doesn’t join the royal family… The day will be an upbeat, fun, military fanfare. No one wants the focus of the celebratory day to be the Princess of Wales.”

Kate Middleton is married to Prince William, who is heir to the British throne. (Henry Nicholls/AFP/Getty Images)

Christopher Andersen, author of “The King,” agreed that the Prince and Princess of Wales have been “closer than ever” as they attempt to navigate the disease behind palace doors.

“William and Kate have always been close, but never closer than they are now,” Andersen told Fox News Digital. “They are both deeply concerned about the impact all these serious health issues are having on their children. Don’t forget that this is all taking place less than two years after Queen Elizabeth’s passing. Their great-grandmother’s death and funeral shook them to some degree.”

“King Charles’ desire for a slimmed-down monarchy must be the farthest thing from his mind at the moment,” said Andersen. “With Kate sidelined for God knows how long and Prince Harry, his wife Meghan and Prince Andrew out of the picture — not to mention William understandably distracted by what’s happening with his wife — the king needs all the help he can get.”

Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex ride by carriage during Trooping the Colour 2018 on the Mall in London on June 9, 2018. The couple won’t be in attendance this year. (Samir Hussein/Samir Hussein/WireImage/Getty Images)

Royal expert Ian Pelham Turner claimed to Fox News Digital that rumors of marital woes during Kate’s battle with cancer are simply “untrue.”

“I have been told by those close to the couple this is totally unfounded,” he said.

“By all accounts, Prince William and Catherine are as close as ever,” chimed British royals expert Hilary Fordwich. “William has been a stalwart support for her, with the Middleton family all supporting her.”

Britain’s Prince William, Prince of Wales, talks with D-Day and WWII Normandy veterans in Southsea Common, southern England, on Wednesday, following the U.K.’s national commemorative event to mark the 80th anniversary commemorations of D-Day landings in France in 1944. (Leon Neal/Pool/AFP via Getty Images)

“At the D-Day anniversary event he assured a veteran, who inquired regarding her health, that she was faring well with her cancer treatment, stating, ‘Yes, she is getting better. She would have loved to be here today,’” Fordwich pointed out. “He added the Princess would have loved to join him for the ‘very moving’ event and confirmed she was ‘getting better.’”

All the royal experts agreed that William was prioritizing his wife’s health. The mother of three, 42, isn’t being rushed to return to royal duties or make a grand appearance. But hope is still there among them.

“I’m hoping that Kate will make an appearance on the Buckingham Palace balcony and that the reaction from the crowd will be thunderous,” said Andersen. “It’s such a highly symbolic moment — one that speaks to the strength of the royal family and the future of the monarchy — if she could muster the strength just to show up and wave, it would mean everything to the king.”

King Charles III and his daughter-in-law are both battling cancer. (Getty Images)

“Let’s not take our eyes off the king, either,” Andersen continued. “In the midst of his cancer treatment, King Charles III intends to review the troops, although this time his doctors have told him he cannot do it on horseback as he did last year. Instead, he will ride to the ceremony in a State Landau carriage, as his mother Queen Elizabeth did in the latter years of her reign. Obviously, Kate is the most beloved royal at the moment, but the public has rallied to the king’s side as well.”

In her March 22 video message announcing she was undergoing chemotherapy, the princess thanked well-wishers for their “wonderful messages of support.”

“It has been an incredibly tough couple of months for our entire family. But I’ve had a fantastic medical team who’ve taken great care of me, for which I’m so grateful,” she said.

Kate added that after cancer was discovered, she was advised to undergo “preventative chemotherapy, and I’m now in the early stages of that treatment.” She said she had told her three children — Princes George, 10, and Louis, 6, and Princess Charlotte, 9.

Kate Middleton announced to the world she had cancer in a prerecorded message shared earlier in March. (The Prince and Princess of Wales Twitter)

“I am well and getting stronger every day by focusing on the things that will help me heal in my mind, body and spirits,” said the royal. “Having William by my side is a great source of comfort and reassurance, too, as is the love, support and kindness that has been shown by so many of you. It means so much to us both.”

She also mentioned her work, saying it “has always brought me a deep sense of joy, and I look forward to being back when I move on. But, for now, I must focus on making a full recovery.”