Crown Princess Amalia of the Netherlands has broken her arm after falling from her horse on Tuesday, the Royal Palace announced, adding that she was being operated on in hospital.
"As soon as it becomes clear what consequences there may be for any official duties, more information will follow," the palace said in a statement.
Amalia, the daughter of King Willem-Alexander, has gradually been assuming a greater role on the public stage now she has turned 21.
She took part in her first official engagement during a state visit last year.
It also emerged last year that she had been forced to escape to Spain amid threats to her safety.
She lived and studied in Madrid for a year, in an arrangement overseen by the Spanish royals.
Amalia was reportedly mentioned in communications by organised crime groups, leading to fears of kidnapping.
While the threat is not thought to have completely disappeared, she has been able to return to the Netherlands and is thought to be living in Amsterdam.
When she started studying politics, psychology, law and economics at Amsterdam University, much was made of her desire to live in student digs like anyone else.
But she was quickly forced to return to the heavily guarded palace in The Hague.