In 2013, the 55-year-old "Lethal Weapon" actor disclosed that he was suffering from hyperthyroidism — a condition in which the thyroid gland produces too much thyroid hormone in the body. In addition, the actor also announced he's suffering from heart and spinal conditions.
According to the American Thyroid Association, hyperthyroidism can cause multiple symptoms, including nervousness, irritability, increased sweating, heart racing, hand tremors, anxiety, difficulty sleeping, thinning of the skin, fine brittle hair and muscle weakness.
It is not clear what heart condition Li has. He also has some pain related to injuries to his legs and spine sustained over years of performing martial art on film sets.
Back in 2013 during the filming of a Chinese talent show, Li said, "I'm just a regular guy, I'm not Wong Fei Hung, I'm not Huo Yuan Jia [heroes he plays on film]. I'm not a hero. I'm just like you. I'm in pain, but I'm not suffering. I'm happy," the Jakarta Post reported.
As the photo circulated on Twitter, there was an outburst of concern and support for Li by fans.
Li last appeared on the big screen in 2014's "The Expendables 3." Reports released last month state that he might star as the Emperor in the remake of Disney's "Mulan." The martial arts superstar also established the One Foundation in 2007. The goal of the organization is to provide disaster relief and improve children's welfare in China.