Princess of Wales was FORCED to reveal her cancer diagnosis after news threatened to leak: Sources reveal Kensington Palace was contacted about Kate's illness and needed to get ahead of the story… so who revealed her secrets?

The Princess of Wales's video announcement detailing her cancer treatment was rushed out by Kensington Palace aides after her diagnosis had been leaked, the Mail can reveal.

Kate Middleton confirmed she had been diagnosed with cancer and is undergoing 'preventative chemotherapy' for the disease in a video message on March 22.

However, a well-placed source has revealed the timing of the video nothing to do with the speculation that would have come from her missing church on Easter morning, but instead because someone had knowledge of her health condition.

Kensington Palace had been contacted about Kate's diagnosis, leaving no option but to hurry to get ahead of the story, the insider told the Daily Mail's Ephraim Hardcastle column. 

It is unclear as to whether the leak came from within The London Clinic, where the Princess underwent abdominal surgery in January, or from elsewhere.

After weeks of frenzied speculation on social media about her health and well-being, Kate released the candid video message just over a week ago, confirming she is undergoing chemotherapy for cancer.

The princess, 42, spoke about the 'huge shock' after tests identified cancer following her abdominal surgery and the 'incredibly tough couple of months' her family have experienced, with her voice cracking with emotion at times during the footage.

The form of cancer has not been disclosed but the future Queen began a course of 'preventative chemotherapy' late in February, and is said to have a positive mindset for her recovery and is in good spirits, describing herself as 'well and getting stronger every day'.

Prince William and Kate focused on their children, taking the time to sensitively share the state of the princess's health with Prince George, Prince Charlotte and Prince Louis. 

The King, diagnosed with cancer in February, is said to be 'proud' of his 'beloved' daughter-in-law for her 'courage' in speaking about her treatment and has remained in close contact during the past few weeks.

Queen Camilla said this past weekend that the Princess of Wales is 'thrilled' by all the public support when she met two sisters holding posters with the poignant words 'send our love to Kate'. 

The King has been receiving treatment for an undisclosed form of cancer since early February after he had an operation for an enlarged prostate at the London Clinic.

While the monarch stepped back from public-facing duties as he continues to undergo his treatment, he has still been carrying out low-key official duties behind the palace walls.  

Prince William is due to return to public duties after his children return to school following the Easter break.

For now, he will continue to balance supporting his wife and family, and maintaining his official duties as he has done since her operation in January.

It is not known how long Kate will be receiving treatment but it is understood she may be keen to attend events as and when she feels able to, in line with medical advice, although this will not indicate a return to full-time duties.

The King and Princess' recent cancer diagnoses have laid bare Charles' stripped back monarchy.

Queen Camilla stood in for King Charles at the ancient Royal Maundy ceremony in Worcester last week, marking the first time a consort has performed the duty on behalf of the monarch.

Maundy recipients and members of the public gave their well wishes to the King and the Princess of Wales as they met the Queen, who handed out ceremonial coins to people recognised for their community service in the traditional Easter service. 

Charles sat in the Sovereign's Seat inside St George's Chapel on Sunday, while the Royal Family sat in the stalls, as per tradition, during the Easter Sunday service. 

The cancer-stricken monarch had delighted fans as he wished them a happy Easter after arriving alongside Camilla at Windsor Castle, as he made a 'gentle' return to public life in his most significant appearance since his diagnosis.

The 'happy' 75-year-old was seen smiling and waving at well-wishers as he arrived in his maroon state Bentley limousine for the service being held at St George's Chapel. 

The King's cheery appearance provided great reassurance to the public after the monarch took a step back from his official duties following his diagnosis last month. 

Despite the boost to public morale, however, the Royal Family's Easter service looked markedly different to previous years.

Last year, during his first Easter Service as King, Charles led the Firm - including William, Kate and their children - on foot into the service, while this year he arrived by car to shield him from infection during his treatment - as per doctor's orders.

As is customary, the King sat inside the chapel in the Sovereign's Seat which is situated at the front of the altar, along with his family who were in their usual places in the stalls. 

The layout of St George's Chapel is such that the main congregation sits in a separate section of the church.

Kate, the Prince of Wales and their children were absent from the Easter service as the family spent the holiday together while they adjust to her diagnosis. 

In Charles's pre-recorded Easter speech, there was no mention of family health matters - his own cancer diagnosis and treatment, as well as that of his daughter-in-law.

Instead, the King stressed the importance of acts of friendship 'especially in a time of need' in the personal message broadcast on Thursday as he skipped the Royal Maundy Service. Queen Camilla represented her husband instead.

The pre-recorded audio was the monarch's first public words since Princess Kate revealed she was undergoing chemotherapy.  

He said how Jesus set an 'example of how we should serve and care for each other', and how as a nation 'we need and benefit greatly from those who extend the hand of friendship to us, especially in a time of need'.

While the King did not directly refer to his and his daughter-in-law's health, his words will be interpreted as reflecting on the nation's response to his and Kate's challenges as they continue treatment for cancer.

The King told last month how he had been reduced to tears by the messages and cards of support he received from well-wishers.

Charles, who only acceded to the throne 18 months ago, also reamplified his Coronation pledge 'not to be served but to serve'.

He recorded a Bible reading and, in his brief personal message, described the Maundy money recipients as 'wonderful examples of such kindness' in 'giving so much of their lives to the service of others in their communities'.

He also re-amplified his own Coronation pledge: 'Not to be served but to serve.'

The message was recorded as an audio instead of on video as Worcester Cathedral does not have the capacity to play a television message.