Edoardo Mapelli Mozzi
Mapelli Mozzi already has a son, Christopher Woolf, from a previous relationship.
The princess remodeled a gorgeous gown previously worn by her grandmother, Queen Elizabeth.
Beatrice also borrowed the tiara that the queen wore on her wedding day in 1947.
A small number of guests were also there, Buckingham Palace has confirmed.
WHAT'S HAPPENING
Beatrice and her fiancé, Edoardo Mapelli Mozzi, were supposed to marry in May.
The royal and her fiancé, Edoardo Mapelli Mozzi, are nixing their Buckingham Palace garden reception.
It'll be a spring ceremony for Prince Andrew's daughter and Italian real estate magnate Edoardo Mapelli Mozzi.
The wedding will take place in 2020, Prince Andrew and the Duchess of York said.