In a statement from the royal family, it was stated that the 85-year-old King was hospitalized for infection and was treated with antibiotics.
It was noted that the condition of King Harald V is stable and will stay in the hospital in the capital Oslo for a few days.
The King of Norway was taken to Oslo University Hospital on 4 August due to fever.
The king caught Kovid-19 on March 22 and took a break from his duty for a few days, leaving his place to his son and heir to the throne, Prince Haakon.
King Harald V, who received three doses of Kovid-19 vaccine, had several health problems in recent years and had heart valve surgery in 2020.