The love child of Belgium's former king, Albert II, took her fight for recognition to court on Thursday as she battles to be granted the same rights and titles as her royal half-siblings.
Artist Delphine Boël, 52, was officially legitimised by the former monarch in January this year after a DNA test showed he was her father, ending a decade-long legal dispute to prove her paternity claim.
Taking her case to an appeals court in Brussels, Boël is now seeking the same rights and titles as Albert's three children, including the current sovereign Philippe.
This includes the right to bear the title of princess of Belgium and use the surname Saxe-Coburg.
"Delphine's position isn't that she wants or doesn't want to be princess," said her lawyer, Marc Uyttendaele.
"She doesn't want to be a cut-price child, she wants to have exactly the same privileges, titles and qualities as her brothers and her sister."
If successful in her bid, Boël's children could also claim the title of prince or princess of Belgium.
The former king's legal team contend that it is not for the court to confer the titles on Boël but for the monarch by decree.
"Today, we discussed what Madame Boël considers to be the accessories of this request for recognition, that is to say the question of the name and the bearing of the title of princess of Belgium," said Alain Berenboom, the king's legal counsel.
He added: “On this point, the king recalls in any case that the law must be applied. For the name, it is rather an administrative procedure than a judicial one, it seems to us. As far as the title is concerned, it is not a prerogative of the court but a prerogative of the executive power, in our opinion."
Rumours surrounding Boël's paternity first arose in 1999 when the allegations were made in an unauthorised biographer of Queen Paola, Albert's wife, causing a scandal.
Boël's mother, Baroness Sybille de Selys Longchamps, claimed to have had an 18-year-long affair with then Prince Albert.
Boël first alleged the king was her father in an on the record interview in 2005. Her legal battle began in 2013 when the king abdicated the throne, thereby losing his immunity from prosecution.
Despite resisting court orders, the 86-year-old submitted to take a paternity test by a Belgian court, the results of which were kept secret until January when the former king accepted Boël as his child.
Albert became King of the Belgians in 1993 following the unexpected death of his brother, King Baudouin.
Belgium is a constitutional monarchy with the role of the sovereign largely ceremonial.