Following a self-test which revealed a positive result, Hereditary Grand Duke Guillaume has placed himself in self-isolation, according to an announcement from the Grand Ducal Court.

"A PCR test subsequently confirmed a positive result and thus His Royal Highness remains in isolation, in accordance with the provisions of the amended law of July 17, 2020 relating to measures in place to combat the COVID-19 pandemic," read a statement from the palace.

"His Royal Highness is currently symptom-free and is doing well. He will resume his duties after the period of isolation," the statement concluded.

The result comes one week after the palace confirmed Grand Duke Henri had entered into quarantine.