Meghan Markle and Kate Middleton are sisters-in-law since they are married to Prince Harry and Prince William, respectively. Both women have something in common with Princess Diana and Sarah Ferguson, who were also sisters-in-law, as the ex-wives of Prince Charles and Prince Andrew.

Despite the commonality, the friendship between Meghan and Kate is a lot different to the relationship between Princess Diana and Sarah, who is more commonly known as Fergie. Though it appears that Meghan and Kate get along, such as when they hang out during Wimbledon in 2019, Princess Diana and Fergie have a longer history as friends.

According to the Duchess of York in an interview with Harper's Bazaar, she and Princess Diana actually grew up together because they are fourth cousins. Their mothers were best friends thus Fergie and Lady Diana have known each other since they were kids.

The book "Sarah: HRH The Duchess of York" revealed that Fergie met and fell in love with Prince Andrew because of Princess Diana. Apparently, Prince Charles' wife set up her childhood friend with her husband's brother to make her life inside the royal walls easier. Royal experts said that Princess Diana was very thrilled when Prince Andrew and Fergie got married.

In the 1980s, Prince Charles, Princess Diana, Prince Andrew and Fergie would have family holidays together. They were the Fab Four at that time and constantly grabbed the headlines if they were seen as a foursome.

Like Fergie, Meghan came into the royal family years after Kate married Prince William. Though Meghan and Kate do not have a deeper relationship compared to the older female royals, the Duchess of Sussex was embraced by the royals as Prince Harry's better half. It was also known that Kate and Prince William often have the Sussexes over their house in Kensington, especially in the early months of Prince Harry and Meghan's marriage.

However, Princess Diana and Fergie were also pitted in the press which loved to compare the two royal wives. In the same way, Meghan and Kate were also heavily compared to each other.

Royal biographer Andrew Morton said that the press pitting Meghan and Kate have been quite predictable. Morton said that as with Lady Di and Fergie, the younger sisters-in-law ere set up for a failure by the media.

Royal experts said that Lady Diana and Fergie were actually quite competitive as women. As in-laws, however, they were very supportive of each other since they faced similar issues, such as their failed marriages.