The couple's respective mothers - Caroline and Countess Donna Paola Marzotto - released a statement expressing their happiness over their new family member's arrival. "The Princess of Hanover and the Countess Paola Marzotto have the joy of announcing the birth of their grandson born on 28 February 2017. The mother and the child are doing well," the statement read.
HOLA! learned on Tuesday that Pierre and his wife had welcomed a son. Rumours of the baby's arrival began swirling on Tuesday after Beatrice's sister posted a (now deleted) mysterious message on Instagram. Attached to a scenic photo of a marina, Matilde Borromeo wrote, "28/2/2017 new date to add in the calendar for my family," adding several blue heart emojis.
Sources confirmed to HOLA! back in November that the couple was expecting their first child together. Beatrice, 31, sparked pregnancy rumours in August, stepping out with a small bump during the Copa del Rey Mapfre Sailing Cup awards ceremony.
The couple's baby news came a few months after they celebrated their first wedding anniversary. Princess Grace's grandson, 29, and Beatrice were married in a civil ceremony in July 2015 in Monaco, followed by a religious ceremony in August on the bride' s family - owned Borromean Islands in Italy.
Last March, Beatrice opened up about her desire to have children. She told Glamour magazine, "I come from a big family, and I want children of my own." Though at the time she noted, "But at the moment I'm thinking about putting my career in a place where it would not get threatened by the presence of children."
Beatrice and Pierre's son marks the fourth grandchild for Princess Caroline. The Monaco royal's son Andrea Casiraghi and his wife Tatiana Santo Domingo welcomed their son Sacha, in 2013 and daughter India in 2015. Caroline's daughter Charlotte Casiraghi is also a mom to Raphaël, whom she shares with her ex-boyfriend actor Gad Elmaleh.