King Philippe of Belgium met his half-sister Princess Delphine de Saxe-Cobourg Gotha for the first time on Friday at Castle of Laeken.
MORE: King Albert II's illegitimate daughter granted princess title
The estranged siblings shared a joint message on the Belgian royal family's official Facebook page, describing the "warm meeting" as "the opportunity to get to know each other".
The full message read: "On Friday 9 October we met for the first time at the Castle of Laeken. It was a warm meeting.
"This extensive and special conversation gave us the opportunity to get to know each other. We have spoken about our own lives and our common interests. This band will develop further in family context."
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The royals shared the post on Instagram
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Delphine was granted the title of Princess of Belgium following a court battle earlier this month.
She was born from King Albert II's 18-year-long affair with Baroness Sybille de Selys Longchamps.
Rumours that he had fathered a child with another woman first emerged back in 1999, after claims were disclosed in an unauthorised biography about Albert's wife, Queen Paola.
Delphine is Albert's daughter
King Albert admitted that he is the father of an illegitimate daughter in January.
King Albert, 85, fought the paternity claim by 51-year-old artist Delphine for more than a decade.
In a statement released by his lawyers at the beginning of the year, Albert was said to have "learnt the results of the DNA test... [and] the scientific conclusions indicate that he is the biological father of Mrs Delphine Boël".
Ms Boël first publicly alleged that Albert was her biological father in a 2005 interview, but it was not until the king abdicated in 2013 that she opened court proceedings.
Her mother, Baroness Sybille de Selys Longchamps, has stated that she had an affair with the royal between 1966 and 1984, when he was still Prince Albert of Liege.
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