"I know what a mother feels so I have tears of joy. I am so proud of this sensational news. Andrew and I are just the luckiest people ever to have two great sons in law,” she wrote alongside a series of images of the couple.
"@princesseugenie took the colour photographs as my girls are so close. Beatrice and Edo wanted her to capture this special moment. The black and white photographs were taken by Misan Harriman," Fergie finished.
Beatrice and Edoardo’s engagement news was confirmed in an official statement from Buckingham Palace.
WATCH: Everything you need to know about Beatrice and Edoardo's wedding
“The Duke and Duchess of York are delighted to announce the engagement of Her Royal Highness Princess Beatrice of York to Mr. Edoardo Mapelli Mozzi.
"Her Royal Highness and Mr. Mapelli Mozzi became engaged while away for the weekend in Italy earlier this month. The wedding will take place in 2020. Further details will be announced in due course.”
Royal fans believe the couple will wed in Edoardo’s homeland of Italy, however, this would rule out Queen Elizabeth II’s attendance.
"I think in her heart Beatrice would like to be married in Italy where Edo’s from, but there’s no way the Queen will fly to Europe for the wedding so it will have to be in England,” royal expert Ingrid Seward told OK Magazine.