Queen Camilla is expected to step in and support her husband King Charles following news of his cancer diagnosis.
Although it's not known how the queen will actively support His Majesty, it is anticipated that Camilla, 76, will assist her husband whilst continuing to carry out public duties.
HELLO!'s royal editor Emily Nash says: "The Queen will be a tower of strength for the King as he goes through cancer treatment. She understands the issue well from her work with Maggie's cancer centres and she will be at his side every step of the way."
Other working members of the royal family could undertake additional duties on behalf of the King but it is understood planning for future state visits will continue where possible. Prince William could take on some of the King's work as he is expected to return to public duties on Wednesday following his wife Princess Kate's planned abdominal surgery.
News of Charles's cancer diagnosis emerged on Monday evening via a statement from Buckingham Palace. It read: "His Majesty has today commenced a schedule of regular treatments, during which time he has been advised by doctors to postpone public-facing duties. Throughout this period, His Majesty will continue to undertake State business and official paperwork as usual.
"The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure. He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible.
"His Majesty has chosen to share his diagnosis to prevent speculation and in the hope it may assist public understanding for all those around the world who are affected by cancer."
Buckingham Palace have not confirmed the type but have said that it is not prostate cancer.
In a briefing, the Palace said: "His Majesty has been treated for benign prostate enlargement. It was during this intervention that a separate issue of concern was noted and subsequently diagnosed as a form of cancer. This second condition will now receive appropriate treatment.
"No further details are being shared at this stage, but His Majesty is receiving expert care and looks forward to returning to full public duty as soon as possible."
The briefing note added: 'His Majesty is grateful to his medical team for their expert care and swift intervention, is wholly positive about his treatment and looks forward to returning to full public duty as soon as possible."
Charles's cancer diagnosis comes after he was treated for an enlarged prostate at The London Clinic. As ever, Queen Camilla was on hand to support the King, travelling to visit Charles every day during his three-night stay at the hospital.
She offered a rare update as she officially opened a new Maggie's cancer support centre at the Royal Free Hospital in northwest London on Wednesday. Upon arrival, she was introduced to donors including Sir Gerald Ronson, who asked after the King's health. "He's getting on, doing his best," she replied.
Meanwhile, when Dori Dana-Haeri, who led the fundraising effort for the new centre, said she was "so pleased" Charles was well, the Queen nodded and said: "Thank goodness."
Camilla's continued support for Charles is nothing new. Her sister, Annabel Elliot, described Camilla as the King's "rock" during the BBC's recent documentary titled Charles III: The Coronation Year. Musing on their marriage, Annabel said: "She is his rock, and I can't actually emphasise that enough. She is somebody who is completely loyal, and she isn’t somebody who has huge highs and lows."