Alexandre Grimaldi-Coste

On 26 October 2006, Albert II gave an interview to USA television personality Larry King during which he said his children would not be in line for the Monegasque throne but that they would be taken care of financially. They are also heirs to Prince Albert II's personal fortune, estimated at more than one billion dollars: Upon joining the Council of Europe on 5 October 2004, Monaco became subject to the European Convention on Human Rights regulations on inheritance rights, in addition to its own national laws, which guarantees familial inheritance for children born out of wedlock.

Born out of wedlock as Éric Alexandre Stéphane Tossoukpè, his mother changed her surname to Coste on 10 November 2004. Daughter of a merchant in Togo where she grew up, she became a student in France when she was 17. She was a flight attendant on an Air France plane en route from the French Riviera to Paris in July 1997 when Albert, a passenger, asked for her phone number, subsequently engaging in a relationship with her for several years until, allegedly, Albert's father, Prince Rainier III, demanded that he end the affair. Coste told Paris-Match that she became pregnant only after a visit to celebrate her 31st birthday turned into a tryst. Albert provided for and visited mother and child promising, according to Coste, to legally acknowledge the child after a DNA test confirmed his paternity. When he did not do so, Coste offered the interview and photographs to the media. Albert made no public comment on media speculation, being in official mourning following the death of his father. Although he successfully sued Paris-Match for invasion of privacy, he did acknowledge paternity of the child in a statement issued by his attorney, Thierry Lacoste, on 6 July 2005. In an April 2014 interview Nicole Coste noted that she had legally changed Alexandre's surname to Grimaldi-Coste, adding the dynastic name used by the princely family.

Alexandre Grimaldi-Coste (born 24 August 2003) is the son of Albert II, Prince of Monaco, and Nicole Coste. Since his parents have never married, Grimaldi-Coste is not in the line of succession to the Monegasque throne.

Out-of-wedlock children are not in the line of succession to the Monegasque throne according to Article 10 of the Constitution of Monaco, as amended 2 April 2002 by law n°1.249, which specifies that only "direct and legitimate" descendants of Monaco's monarch (or of the monarch's siblings) may inherit the throne. Article 227 of the Monegasque Civil Code provides that if the parents of a (non-adulterine) child marry, the child is legitimized ipso facto (as happened in 1995 when Princess Stéphanie of Monaco married the father of two of her children). A child born out of wedlock may be legitimated in Monaco: Article 226-9 of the Monegasque Civil Code specifies that "the legitimization can benefit all children born out of wedlock provided that, by voluntary acknowledgement or by court judgement, their parentage has been lawfully established with regard to their two parents". The law of the principality stipulates, however, that a child of the reigning prince born out-of-wedlock may only inherit the throne if he weds the child's mother.

Illegitimate children are nothing new in the Princely Family of Monaco — in every generation for the last 100 years a Grimaldi has had an acknowledged illegitimate child. Some of these have obtained succession rights through legitimation or adoption, including Princess Charlotte, Duchess of Valentinois, an illegitimate child who was adopted by her own father, and who then ceded her succession rights to her son Rainier, 30 May 1944. Prince Rainier III made obtaining succession rights in this manner impossible for the illegitimate children of his son Albert by adopting a new constitutional amendment in 2002, which limited the succession to direct, legitimate issue.