Prince William and Prince Harry should put aside their differences for their father, King Charles III, who was recently diagnosed with cancer, according to a royal expert.

Buckingham Palace announced on Monday that the monarch had been diagnosed with some form of cancer. American journalist Christopher Andersen, author of "The King," weighed in on the royal siblings' relationship. For him, it's high time that the Duke of Sussex and Prince of Wales work on their relationship, given that His Majesty is reportedly thrilled to reunite with his youngest son. Prince William and Prince Harry

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Prince William and Prince Harry attend the opening of the Greenhouse Sports Centre on April 26, 2018 in London, United Kingdom.

"Sometimes it takes a crisis like this to bring families together, and, in that sense, the royal family is no different from any other," Andersen told Fox News. "I do think this is a moment when real progress can be made in bridging the gap between Harry and the rest of the royals. We will have to wait and see whether they seize that opportunity or are simply unwilling to budge."

However, he added that it wouldn't be easy for both since the rift had gone down deep.

"Both sides are pretty well entrenched at this stage," Andersen continued. "There's a lot of bad blood. ... These people are rather pig-headed, very strong-willed and not inclined to compromise. But, then again, Harry will ... certainly want to lend his support to the king in any way you can."


Kate Middleton, Prince William and Prince Harry
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Prince William, Kate Middleton and Prince Harry attend the official opening of The Global Academy in support of Heads Together at The Global Academy on April 20, 2017 in Hayes, England.

Royal expert Ian Pelham Turner, an international TV broadcaster, is convinced that Prince Harry "will try to build bridges" with his dad and big brother. However, some sources have claimed that a reconciliation would be unlikely.

"I think William would rather shoot himself than see his brother right now. I think this is very deep. This is a real sibling war," said Piers Morgan, English broadcaster, journalist, writer and TV presenter, when he appeared on "Today" and spoke about the relationship between King Charles' sons.


Prince William, Kate Middleton and Prince Harry
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Prince Harry, Kate Middleton and Prince William laugh as they host a tea party on the grounds of Buckingham Palace to honour the children of those who have died serving in the armed forces on May 13, 2017 in London, England.

Morgan pointed out Prince Harry's alleged attacks against the royal family, including Prince William and Kate Middleton. He added that the Duke and Duchess of Sussex trashing the royal family for years "is not conducive to a sibling relationship."

An old school friend of Prince William and Prince Harry, who chose to be anonymous, also said that the heir apparent had no plans of reconnecting with his younger brother despite their father's cancer diagnosis.

"The news about their father is absolutely shocking, but I don't think it means William wants to meet up with Harry and shake hands for the cameras," the insider said.


Royal family
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Prince Charles, Queen Elizabeth II, Camilla, Prince William, Kate Middleton, Prince Harry and Meghan Markle during a reception to mark the 50th Anniversary of the investiture of The Prince of Wales at Buckingham Palace in London on March 5, 2019.

"The idea that William and Kate are ever, ever going to let Harry back into their lives or trust him with any personal information ever again is a total fantasy. It's simply not possible to exaggerate how bad and how damaged the relationship is, and how angry William is at Harry for betraying him for money."

Prince Harry already returned to California after a 45-minute meeting with King Charles. He reportedly didn't see Prince William during the trip.