"Greetings from Norway! Sorry to say that I, today, have tested positive for COVID19, Corona virus," the 41-year-old actor wrote alongside a selfie of him and his wife, Gry Molvær Hivju.
"My familiy [sic] and I are self-isolating at home for as long as it takes. We are in good health - I only have mild symptoms of a cold," he continued. "There are people at higher risk for who this virus might be a devastating diagnosis, so I urge all of you to be extremely careful; wash your hands, keep 1,5 meters [1.6 yards] distance from others, go in quarantine; just do everything you can to stop the virus from spreading."
The "Witcher" actor went on to note that "together we can fight this virus and avert a crisis at our hospitals."
He added, "Please take care of each other, keep your distance, and stay healthy! Please visit your country's Center for Disease Control's website, and follow the regulations for staying safe and protecting not just yourselves, but our entire community, and especially those at risk like the elderly and people with pre-existing conditions."
Hivju isn't the first Hollywood star to test positive for the novel virus.
Actor Idris Elba also announced on Monday that he has tested positive for coronavirus (COVID-19).
Last week, Tom Hanks and wife Rita Wilson also announced that they had coronavirus. Hanks and Wilson were in Australia filming an untitled Elvis Presley biopic directed by Baz Luhrmann, with Hanks playing Presley's manager, Colonel Tom Parker.
For most people, the new coronavirus has caused only mild or moderate symptoms, such as fever and cough. For some others, especially older adults and people with existing health problems, it could cause more severe illness, including pneumonia.
The Associated Press contributed to this report