Grace Kelly's daughter, Princess Caroline of Monaco, has become a first-time grandmother.

The royal's eldest son Andrea Casiraghi and his fiancee, Tatiana Santo Domingo, welcomed a baby boy on Thursday (21Mar13).

A representative for the Monaco palace announced the happy news on Friday (22Mar13), revealing 56-year-old Princess Caroline is overjoyed by the latest addition to the European royal family.

The baby, whose name has yet to be released, is the great-nephew of the country's ruling sovereign, Prince Albert Ii.