In 1986, Princess Diana went to Fergie's hen's party. They both got arrested.

Princess Diana was out celebrating Sarah Ferguson's hens' party in 1986 when the pair found themselves in the back of a police van. 

Recalling the incident on The Kelly Clarkson Show this week, Fergie shared that she and Diana, who was married to then-Prince Charles, went out to a nightclub dressed as police officers ahead of her wedding to Prince Andrew.

"It was extraordinary, because we went to a nightclub - of course, you go to a nightclub with the Princess of Wales," the 63-year-old recalled.

"We sat down and the waiter came up to us and said, 'Excuse me, this is a members' club. It’s for fun, and we don’t serve police officers here.'"

After leaving the club, the pair, who were then in their 20s, ended up being arrested for impersonating police officers! The royal duo were taken to a police van, where they tried to hide their engagement rings.

"We got in the back of the van, [Diana] had put her engagement ring round the other way and I put mine round the other way," Fergie explained. 

While in the police van, Diana noticed a packet of smoky bacon flavoured chips and "started taking them and eating them", Fergie added.

"The policeman in the front said, 'You can't do that!' and then eventually they realised that it was Diana and me."

Later that night, they returned home and locked Prince Andrew out of Buckingham Palace as he returned from his bachelor party, according to the ABC.

Image: The Kelly Clarkson Show.

Diana and Fergie were friends long before they became royals. The pair were fourth cousins and their mothers were best friends at school. 

"I loved her from the minute I met her when I was 14 to the minute she passed away," Fergie told The Telegraph in 2021. 

"There was nobody like her and there never will be."

However, a rivalry reportedly arose between the two after Fergie married Andrew.

"[Fergie] wooed everybody in this family and did it so well. She left me looking like dirt," Diana told her biographer Andrew Morton.

She also claimed Charles told her, "I wish you would be like Fergie - all jolly."

The former sister-in-laws later had a falling out the year before Diana's death in 1997.

Speaking to Harper's Bazaar in 2007, Fergie said she "never knew the reason" behind the rift. 

"I tried, wrote letters, thinking whatever happened didn't matter, let's sort it out," she told the publication. 

"And I knew she'd come back. In fact, the day before she died she rang a friend of mine and said, 'Where's that Red? I want to talk to her.'" 

During The Kelly Clarkson Show, the Duchess shared memories of Diana, who she referred to as 'Dutch'.

"Everyone always says to me, 'You must miss Dutch', [but] I go no and I laugh because she's with me all day."

Fergie added that Diana made her laugh "a lot" and the pair often "got into trouble". 

"She used to tell me the worst story, joke story just before I had to be serious," she recalled.

Feature Image: Princess Diana Archive/Getty/The Kelly Clarkson Show.