Charlotte Casiraghi and Gad Elmaleh
Pascal Le Segretain/Getty
08/06/2013 at 03:00 PM EDT
Princess Caroline of Monaco's happiness streak continues.
After PEOPLE reported that her son Andrea Casiraghi is set to tie the knot
with his fiancée, South American heiress Tatiana Santo Domingo, on Aug. 31, sources confirm that the Princess's daughter, Charlotte Casiraghi, is expecting her first child with French comedian and actor Gad Elmaleh before Christmas.
The good news doesn't end there: Charlotte, 27, and Morocco-born Elmaleh, 42, are also engaged and plan to wed this fall in a private ceremony.
"Theirs is a beautiful love story and now there is a baby on the way,” a friend of Elmaleh tells PEOPLE. "It's a proud moment for them."
The late Princess Grace's granddaughter met Elmaleh in November 2011 at the home of a mutual friend. The baby on the way will be the first for Charlotte and the second for Elmaleh. He is father to son Noé, 12, from a previous relationship with French actress Anne Brochet.
Charlotte, a champion equestrian and a model for Gucci's Forever Now campaign, is the third in line to succeed Prince Albert II as Monaco's ruling sovereign.