Sarah Ferguson and Princess Beatrice. Picture: Bang Showbiz

Sarah Ferguson cried when she found out her daughter Princess Beatrice was engaged to Edoardo Mapelli Mozzi.

The 59-year-old writer and her ex-husband Prince Andrew feel like the "luckiest people ever to have two great sons-in-law" after their eldest daughter got engaged to property tycoon Edoardo Mapelli Mozzi during a recent weekend break in Italy.

Taking to her Instagram account, the charity patron - who is also known as "Fergie" - wrote: "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 (sic)."

Princess Beatrice and Edoardo - who began dating in October last year - announced their happy news via Buckingham Palace on Thursday morning.

They said: "We are extremely happy to be able to share the news of our recent engagement. We are both so excited to be embarking on this life adventure together and can't wait to be married. We share so many similar interests and values and we know this will stand us in great stead for the years ahead, full of love and happiness."

Edoardo's parents, Nikki Williams-Ellis and Alessandro Mapelli Mozzi are "delighted" that their son is going to marry Beatrice next year as they share a "strong and united bond."

They said: "We are truly delighted about Edoardo and Beatrice's engagement. Our family has known Beatrice for most of her life.

"Edo and Beatrice are made for each other, and their happiness and love for each other is there for all to see. They share an incredibly strong and united bond, their marriage will only strengthen what is already a wonderful relationship."

The 34-year-old property developer - who has a child from a previous relationship - made his first public appearance with Beatrice, 31, at the National Portrait Gallery gala in March and they have been spotted together several times since then.

Sarah and Andrew's other daughter Eugenie, 29, married Jack Brooksbank last year.