Antoinette Louise Alberte Suzanne Grimaldi, Princess of Monaco, Baroness de Massy, was born in Paris on December 28, 1920. She is the elder sister of Prince Rainier III of Monaco. Her parents were Princess Charlotte of Monaco (née Charlotte Louise Juliette Louvet, a daughter of Prince Louis II of Monaco, born out of wedlock, who was legitimated by ordinance of Prince Albert I in 1919), and Prince Pierre Marie Xavier Raphael Antoine Melchior Grimaldi (né de Polignac), Duke and Duchess of Valentinois.
Three children were born to Princess Antoinette and her lover Alexandre-Athanase Noghès, heir to a cigarette fortune: Elisabeth-Anne, Christian Louis, and Christine Alix. The parents subsequently married in 1951: their children bear the title "Baron/Baroness de Massy". The couple divorced in 1954.
Her second husband, Jean-Charles Rey was married to her from 1961 to 1973.
Her third husband was John Gilpin, a noted Britishballet dancer, whom she married in 1983 and who died two months later.
Three children were born to PrincessAntoinette and her lover Aleco Noghès, the Monegasque-born heir to a cigarette manufacturing fortune: Elisabeth-Anne (born 1947), Christian Louis, (born 1949), and Christine Alix (1951–1989).
PrincessAntoinette is known to be somewhat eccentric, even having been described as "completely mad" by her servants and she lives down the coast from Monaco at Èze with a large collection of dogs and cats.
PrincessAntoinette and her descendants lost their place in the line of succession to the Monegasque throne, which they acquired in 2002 with the reform of the succession rules, with the death of Rainier III.