Since Fergie and the Duke of York divorced in 1996, people were naturally a little confused as to why she was celebrating their anniversary.
"I wouldn’t celebrate a divorced marriage?! Good they still speak etc, but still?!" one person commented.
"I’m confused, are they back together??? I thought they were divorced???" someone else wrote.
"I would only do it if they were still married I wouldn’t want to upset them if they were divorced," another commenter wrote.
For the most part, though, people celebrated Prince Andrew and Fergie for still being friends and successfully co-parenting their daughters, and even expressed hope that they might get back together one day.
"It would be amazing if they were to re-marry... a first within the royal family surely?" one person wrote.
Eugenie has once called her parents "the best-divorced couple I know," adding that they always went out of their way to make her and her sister Princess Beatrice "feel secure."
But when asked by the Daily Mail in 2010 if he and Fergie would ever get married again, Prince Andrew said, "No. We are both in a better place. It’s because we are in a better place which is probably why we are able to remain such close friends. We have two great kids. We do things together as a family."
Even if a reunion isn't in the cards, it sounds like Prince Andrew and Fergie have remained on great terms.
This article originally appeared on InStyle US.