Catherine, Princess of Wales holds onto her hat in the wind as she attends the 2023 Commonwealth Day Service at Westminster Abbey on March 13, 2023

Kate Middletonovercame her “inherently shy” nature to deliver some difficult news.

In a video released on March 22, the Princess of Wales told the world that she wasundergoing treatment for cancerdiscovered in post-operative tests following herJanuary abdominal surgery.

Royal biographer Sally Bedell Smith tells PEOPLE that Princess Kate, 42, was “sincere, dignified, poised, and she was forthright” in her delivery, but the announcement likely wasn’t easy.

“She is inherently shy, and for her to do that took a lot,” Bedell Smith adds.

While the health update was extremely personal, Princess Kate acknowledged the many others who are also facing cancer, echoing something the lateQueen Elizabethmay have done.

“When she ended with ‘You are not alone,’ it rang a bell with something that Queen Elizabeth would have said,” Bedell Smith explains. “It was very similar towhat Queen Elizabeth said during COVIDwhen she said, ‘We are all in this together.’ "

“She was mindful there are very few people who read about that or watched that who doesn’t know someone who has cancer. She was mindful of that,” the journalist and biographer continues. “It was a way of reassuring people not only about her condition but helping them have courage.”

“There was not a trace of self-pity. She projected honesty,” Bedell Smith says. “It was the right balance.”

“It is a message from the princess about her health, and she wanted to personally deliver the message on her own,” a palace source tells PEOPLE, adding that the Prince of Wales, 41, has been “supporting her throughout” behind the scenes.

“William is extremely proud of his wife for the courage and strength she has shown not just this week but since her surgery in January,” the source says. “Now more than ever, he’s focused on ensuring his wife has the privacy she needs to fully recover and that his children are shielded from the understandable interest in the news that has been shared.”

Kate Middleton and Prince William attend the Royal Variety Performance on Nov. 30, 2023.DANIEL LEAL/AFP via Getty

Britain’s Catherine, Princess of Wales and Britain’s Prince William, Prince of Wales arrive to attend the Royal Variety Performance at the Royal Albert Hall in London on November 30, 2023.

DANIEL LEAL/AFP via Getty

In her emotional video, Princess Kate thanked well-wishers for their “wonderful messages of support” amid her surgery recovery during she called “an incredibly tough couple of months for our entire family.”

“In January, I underwent major abdominal surgery in London, and at the time, it was thought that my condition was non-cancerous,” the royal mom of three explained. “The surgery was successful. However, tests after the operation found cancer had been present. My medical team therefore advised that I should undergo a course of preventative chemotherapy, and I am now in the early stages of that treatment.”

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Kate Middleton meets military personnel taking part in Queen Elizbeth’s funeral on Sept. 16, 2022.Samir Hussein/WireImage

Catherine, Princess of Wales meets with military personnel during a visit to Army Training Centre Pirbright on September 16, 2022 in Guildford, England. The Prince and Princess of Wales are visiting the training centre to meet troops from the Commonwealth who have been deployed to the UK in order to take part in the funeral of Queen Elizabeth II, which will take place on September 19.

Samir Hussein/WireImage

Calling the news a “huge shock,” Princess Kate said that she and Prince William “have been doing everything we can to process and manage this privately for the sake of our young family. As you can imagine, this has taken time. It has taken me time to recover from major surgery in order to start my treatment.”

source: people.com