HELLO! understands that Archie and Lilibet will remain in Montecito for their schooling. It's likely their mother Meghan will stay too to help look after the kids, while Harry travels solo.
A source close to Harry confirmed: "The Duke did speak with his father about his diagnosis. He will be traveling to the UK to see His Majesty in the coming days."
It is understood that Charles, 75, personally notified Harry of his diagnosis before announcing it to the world in a statement via Buckingham Palace.
The statement read: "During The King's recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer.
"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."
Harry has had a troubled relationship with his father in recent years, but it's hoped that the recent health diagnosis will carve the way for a reconciliation.
Speaking on HELLO!'s A Right Royal Podcast, royal author Robert Hardman – who last month published a new royal book, Charles III New King. New Court. The Inside Story – revealed that the King would "definitely" like to reconcile with Harry.
He described Charles as an "optimist" and "not confrontational", therefore willing to make peace with his younger son.
Harry moved to California in 2020, after living in Canada for a few weeks. He and wife Meghan welcomed their second child, daughter Lilibet, in Los Angeles in June 2021.
The family live in an £11million mansion in the exclusive Californian town of Montecito.