Prince Henrik of Denmark, aged 10, was tested for coronavirus after suffering asthma issues.
The young royal, son of Prince Joachim and Princess Marie, was given the all-clear following the test.
He had been suffering from breathing problems linked to asthmatic bronchitis.
The family are staying at Amalienborg Palace in the Danish capital of Copenhagen while the country is in lockdown.
It comes after another royal, Prince Albert of Monaco, tested positive for coronavirus - nine days after the monarch was in the same room as Prince Charles for a WaterAid event.
The prince was the first head of state and reigning monarch to announce they were battling Covid-19.
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Yesterday, Denmark extended until April 13 a nationwide lockdown that has closed schools and restaurants and kept most public sector workers at home to try to curb the spread of the coronavirus.
The Nordic country, which has reported 24 coronavirus-related deaths, had announced a two-week lockdown to limit physical contact between its citizens on March 11.
"We've changed our behaviour a lot. We've changed the way we co-exist. We keep a distance and we stay at home.
"And that is paramount for the strategy of breaking the chain of infections," Prime Minister Mette Frederiksen told a news conference.
The country has restricted public assembly to 10 or fewer people and ordered the closure of schools, universities, day cares, restaurants, cafes, libraries, gyms and hair salons.
It has also announced economic aid packages worth 55 billion Danish crowns ($7.93 billion) and state guaranteed loans to businesses worth 60 billion crowns to help deal with the economic impact of the coronavirus.
