BEIJING -- US and CBA basketball star Jeremy Lin has reassured his fans on social media on Saturday that he is feeling well and has started treatment after testing positive for COVID-19.

The 32-year-old was diagnosed with the virus on day three of his quarantine upon arrival in Shanghai for his annual summer tour. Before departure, he has been vaccinated in the US, and tested negative twice.

"To be honest, I was shocked and anxious for the first few hours when I was told the result... Still, I'm immensely grateful for the care that I'm getting in Shanghai. Doctors, nurses and hospital staff that risk their lives to take care of patients like me. With their care I'll be at full health soon," Lin wrote on his Weibo account.

Lin returned to the US after the conclusion of the CBA 2019-2020 season, and announced in June that he is coming back for the 2021-2022 season to rejoin the Beijing Ducks.