For her two biggest supporters, the late royal was simply known as "Grannie."
Mapelli Mozzi already has a son, Christopher Woolf, from a previous relationship.
The royal learned that she was dyslexic when she was 7 and now wants to "change the narrative around the diagnosis."
Mozzo also has a son from a previous relationship.
Stuart Camp told how the princess was pretending to knight another famous entertainer when she accidentally struck Sheeran with a ceremonial sword.
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.
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.