Grace Kelly's granddaughter is pregnant and engaged to marry her longterm boyfriend, according to a U.S. report.

Charlotte Casiraghi, the daughter of Princess Caroline of Monaco, is expecting her first child with French comedian and actor Gad Elmaleh.

The happy news comes just hours after the announcement that Charlotte's brother Andrea is preparing to tie the knot with his fiancee, South American heiress Tatiana Santo Domingo, later this month (Aug13).

The baby will be the first for Gucci model Charlotte and the second for Elmaleh who has a son NoƩ, 12, from a previous relationship with French actress Anne Brochet.