Sarah Ferguson and Prince Harry have a great relationship, but the same apparently can't be said of the duchess and Prince William.

The Duchess of York was absent during the ceremony when Prince William married Kate Middleton in 2011. However, Ferguson was present when Prince Harry and Meghan Markle exchanged "I do's" in May. According to Francesca Specter, a journalist for Daily Express, Prince Andrew's ex-wife and the Duke of Sussex get along really well.

An insider who spends holidays at Verbier, a favorite Swiss ski resort among royals, spoke about Prince Harry and Ferguson's "adoration" for each other in 2016. According to the source, the two ski together.

"Harry gets on with Fergie really well. He thinks she’s hilarious, and they have a mutual adoration society," the source said. "He loves being part of her redsetter mob [a Royal Family nickname for her] and they ski together, then gas over mulled wine."

Initially, Ferguson wasn't expected to be present at the Duke and Duchess of Sussex's big day. Her absence wouldn't be surprising to many as she was not present during the Duke and Duchess of Cambridge's royal wedding. However, according to insiders, Prince Harry fought the palace just to invite Ferguson.

"Harry has nailed his colours to the mast on this. He wants his aunt there – and she will be," the insider said.

"Any suggestion she will not be [at the wedding] is a complete fabrication," another insider added. "He absolutely, 100 per cent wants her there and has told palace officials that in no uncertain terms."

According to Specter, Ferguson apparently wasn't invited to Prince William's wedding because she was reportedly caught selling "access" to the Duke of York. Following Prince William and Middleton's nuptials, she confessed that it was difficult for her not to be there.

"I wanted to be there with my girls… to be getting them dressed and to go as a family," Ferguson said when she appeared on "The Oprah Winfrey Show."

The royals and Ferguson's rift reportedly started when a controversial photo showed her cavorting with her financial advisor, John Bryan. However, Ferguson's relationship with the royals has improved since then. In fact, she was seen chatting with the Queen in June during the Royal Ascot.

Ferguson will make a royal comeback on Princess Eugenie's royal wedding. However, this might not sit well with Prince Philip, who reportedly can't stand to be in the same room as the duchess.

Sarah Ferguson
Why did Sarah Ferguson attend Prince Harry's wedding but missed Prince William's? Pictured: Ferguson arrives at St George's Chapel at Windsor Castle before the wedding of Prince Harry to Meghan Markle on May 19, 2018 in Windsor, England. Getty Images/Gareth Fuller