Princess Caroline's first grandaughter is 2 days old and sixth in line
Credit: Monaco Princely/WireImage

Congratulations are in order – yet again – for Monaco.

Prince Albert‘s nephew Andrea Casiraghi and wife Tatiana Santo Domingo had a second child on Sunday in London, sources confirm to PEOPLE. The child, a girl, is Princess Caroline’s first granddaughter and will become sixth in line to the Monaco throne.

Andrea and Tatiana, who already have a 2-year-old son, Alexandre (known as “Sacha”), first announced the pregnancy in November. After dating for a decade, Andrea, the son of Princess Caroline, and Tatiana were married in August 2013.

The birth of the Casiraghi daughter comes just four months after that of Prince Albert and Princess Charlene’s twins, Gabriella and Jacques, in December.

The twins are due to be formally christened in Monaco’s Cathedral on May 10.