The Dutch king and queen apologised on Monday after they were pictured breaking coronavirus social distancing rules while on holiday in Greece.
A photograph on the internet showed King Willem-Alexander and Queen Maxima up close to a man said to be a restaurant owner on the island of Mykonos.
"A photo appeared in the media in which we kept too little distance. In the spontaneity of the moment, we did not pay attention," the king and queen said on Twitter.
"Of course, we should have done. Because on holiday too, respecting rules for coronavirus is essential for beating the virus."
The photo showed the king, 53, in a patterned shirt with a mask in one hand and his arm around the queen, 49, while the man also had his arm around the queen.
The person who took the photo, quoted anonymously by Dutch broadcaster RTL Nieuws, said it was taken in a private capacity and that the failure to respect social distancing was a "mistake".
In March the Dutch royals went into self-isolation after cases of the virus were reported in a part of Austria where they had spent a skiing vacation.
The Dutch government has recently urged citizens to be extra careful to respect social distancing rules after a surge in Covid-19 cases