Prince Albert II has tested positive for the coronavirus, the Monaco Royal Palace has announced.
A statement said Prince Albert II, an International Olympic Committee (IOC) member, was continuing to work from his apartment.
"Prince Albert II, who had tested at the beginning of the week, is COVID-19 positive," it read.
"His state of health does not cause any concern.
"Albert is being treated by his GP and specialists at the Princess Grace Hospital.
"His Serene Highness urges the people of Monaco to respect containment measures and to limit contact with others to a minimum.
"Only the rigorous observance of these containment rules will stop the spread of the virus."
Monaco has reported nine cases of coronavirus to date, including the city-state Prime Minister Serge Telle.
Telle tested positive for the virus three days ago.
Prince Albert is believed to be the first head of state and IOC member to have tested positive for coronavirus.
Prince Albert, who became an IOC member in 1985, currently chairs the organisation's Sustainability and Legacy Commission.
The Royal represented Monaco at five Olympic Games in bobsleigh.
The 62-year-old announced measures earlier this week aimed at halting the spread of coronavirus.
Prince Albert said earlier this week that travel should be limited, with the exception of buying essential food and medicine supplies.
All group activities have been prohibited and building work halted.
The Monaco Formula One Grand Prix has also been postponed.
The event is among the latest sporting competitions to be impacted by the coronavirus pandemic.
International Modern Pentathlon Union (UIPM) President Klaus Schormann said the organisation offered their best wishes to Prince Albert, who is the governing body's Honorary President.
“Our entire global community is in shock about this news and on behalf of the UIPM Family I would like to send our very best wishes to our Honorary President, who has been at the helm of our movement since 1997," Schormann said.
“Prince Albert is a wonderful ambassador and friend, not only to our sport but also the wider Olympic movement through his work as an IOC Member and many other leadership roles.
“We are all hoping that His Highness will enjoy a smooth and quick recovery and be back within our community soon.”
Over 236,000 people worldwide have now tested positive for coronavirus - also known as COVID-19.
Over 9,000 people have died from coronavirus.