Prince Philip's 'petty' reason for missing Princess Eugenie's wedding

It has long been rumoured that Prince Philip is no fan of his former daughter-in-law, Sarah "Fergie" Ferguson.

And now it seems that tense relationship may see him avoid his own granddaughter's upcoming wedding.

While most of the British royal family are expected to attend Princess Eugenie's wedding to fiance Jack Brooksbank, 31, on October 12, one source has told PEOPLE Magazine the Duke of Edinburgh may be noticeably absent on the big day.

"He does what he wants," the unnamed insider recently told the publication.

"He made a supreme effort for Harry. I would be very surprised if he did go, because he is so estranged from Fergie.

"I think he will decide at the 99th hour."

Queen Elizabeth and Prince Philip's third child and second son, Prince Andrew, was married to Fergie for 10 years.

During their marriage, the royal couple had two daughters — Princess Beatrice, 29, and Eugenie.

But the pair split up in 1992, and in 2010, Fergie was caught on film trying to sell access to her famous in-laws to an undercover journalist who was masquerading as a businessman.

While that scandal hasn't seemed to have harmed relations between the former spouses, who have always remained on good terms, it is believed to have caused a rift between Fergie and her former father-in-law.

Princess Eugenie and Jack Brooksbank. Photo / Getty Images

During an interview with Dr Phil after the incident, Fergie claimed he had described her behaviour as "idiotic".

"For such a smart woman, why does she behave in such an idiotic way?" she recalled Prince Philip as say after the embarrassing mishap.

The insider said Prince Philip may also miss the nuptials due to health issues.

While the 97-year-old is in reasonably good health, he did recently undergo a hip replacement just before Prince Harry and Meghan Markle's wedding earlier this year.

Just like her cousin Harry, Princess Eugenie and Mr Brooksbank will tie the knot St George's chapel in Windsor Castle later in the year, with 12000 members of the public set to be invited along with royals and celebrities.

Buckingham Palace announced the engagement of Princess Eugenie and Jack Brooksbank on January 22

The couple have been dating for seven years, and were first introduced by friends in a ski break in Switzerland.

They got engaged during a holiday in Nicaragua, and the pair jointly designed Eugenie's priceless pink sapphire engagement ring.

Princess Eugenie is ninth in line to the throne.