"We are the lucky parents of a wonderful daughter who has found her love and companion in a completely devoted friend and loyal young man. We send them every good wish for a wonderful family future."
Beatrice is set to become the first member of the Queen's family to become a stepmother as Mapelli Mozzi has a two-year-old son from a previous relationship. Camilla is stepmother to princes William and Harry.
Mapelli Mozzi's parents, Nikki and Alessandro, said they too were delighted.
"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 said.
"They share an incredibly strong and united bond, their marriage will only strengthen what is already a wonderful relationship."
Beatrice, 31, started dating Mapelli Mozzi, 34, after her sister Eugenie's wedding. He then moved into Beatrice's apartment at St James's Palace earlier this year.
The multi-millionaire property developer, who has a son with his former fiancé Chinese-American architect Dara Huang, has been a family friend of the Yorks for years.
"We are both so excited to be embarking on this life adventure together," the pair said in a statement.
"We share so many similar interests and values, and we know that this will stand us in great stead for the years ahead, full of love and happiness."
In a touching post on Instagram, Mapelli Mozzi wrote: "You will never be alone my love, my heart is your home. Hand in hand, today, tomorrow and forever."
