Sarah Ferguson could be sitting on a multimillion-dollar payday — but cashing in may cost her what remains of her relationship with the Royal Family.

The former Duchess of York, 66, is reportedly weighing the possibility of a bombshell documentary about her extraordinary life, with streaming giants including Netflix said to be interested.

But there is one major problem.

Any no-holds-barred royal tell-all could put Ferguson on a collision course with King Charles — and potentially create trouble for her daughters, Princess Beatrice and Princess Eugenie, who remain connected to the monarchy.

Ferguson, who separated from Andrew Mountbatten-Windsor in 1992 before their divorce was finalized in 1996, has endured decades of scandals, financial problems and humiliating headlines.

Now, insiders believe her story could be worth a fortune.

“She’s still sitting on a gold mine, and that would be the tell-all book or the Netflix documentary series,” TV presenter Mark Dolan said on The Royals Uncensored.

Former royal butler Grant Harrold believes Ferguson’s daughters may be the biggest reason she ultimately refuses to spill everything.

Harrold, who worked for Charles between 2004 and 2011, said Ferguson is likely well aware that Beatrice and Eugenie still have relationships with the King and remain members of the Royal Family.

“I think that relationship with her daughters, and her daughters are obviously still members of the Royal Family and involved with the King, that’s in the back of her mind,” he said.

Harrold added that despite the enormous commercial possibilities, he doubts Ferguson would risk going too far.

“Even though she might think about doing these books and everything, I personally think she won’t go that far because of her relationship with her daughters, and the King,” he said.

And the financial stakes could be enormous.

One royal source said a documentary featuring Ferguson’s version of decades of palace drama could be extremely lucrative — particularly if producers were given intimate access and she agreed to address the controversies people still associate with her.

“This is exactly the sort of project that could pay very well if it is made with enough access and enough controversy,” the insider said.

The source added that Ferguson would also gain something potentially even more valuable than money: the chance to tell the story on her own terms.

“Sarah has a story people think they know, but a film would let her control the tone, and that is what makes the opportunity so valuable,” the insider said.

But another industry source warned that the check could come with a devastating personal cost.

“The risk is not the money, it is the fallout,” the source said. “A documentary can bring a big cheque, but it can also lock in old resentments and make future family contact far harder.”

That warning could carry particular weight for Ferguson because her relationship with Charles has been surprisingly complicated over the years.

Despite her divorce from Andrew and years of controversy, Ferguson had slowly been welcomed back into certain royal gatherings.

Charles invited her to Christmas at Sandringham, and she also attended Easter services with the Royal Family at Windsor — signs that her position within the royal orbit had begun to thaw.

But Ferguson’s links to convicted sex offender Jeffrey Epstein again created damaging headlines.

Emails later emerged showing Ferguson had remained in contact with Epstein after his conviction for child sex offenses. She has publicly expressed regret over her association with him.

The controversy dealt another major blow to her reputation and her already precarious place around the monarchy.

Now, a splashy streaming documentary could reopen years of scandals just as Ferguson faces an uncertain future.

Charles, 77, has spent much of his reign attempting to project stability while navigating one family crisis after another.

The King has pushed for a smaller working monarchy focused on duty and public service, while controversies involving Andrew, the Sussexes and other members of the extended royal family have continued generating unwanted headlines.

One palace observer said that makes the idea of Ferguson turning royal turmoil into entertainment especially sensitive.

“The King’s priority is not to reward every commercial temptation around the family,” the source claimed. “It is to protect what remains of the institution’s credibility, and that means there are obvious limits to how much a documentary like this can be welcomed.”

Another insider warned that Ferguson could ultimately be forced to choose between a massive payday and maintaining whatever royal goodwill she has left.

“If Sarah does a big documentary for one of the world’s biggest streamers, it would be as much a test of her loyalty to the people around her as a business decision,” the source said.

Millions of royal watchers would undoubtedly be fascinated by Ferguson finally giving her side of decades of palace scandals.

But insiders say the consequences could be permanent.

The money may be tempting. The audience may already be waiting.

Yet if Ferguson decides to tell everything, she could discover that her biggest royal payday also becomes her final goodbye to the palace.