[Update, May 24]: Jet Li has finally broken his silence amid the rumours surrounding his health. 

In a Facebook post on Wednesday, he wrote: "I would like to thank all my fans who expressed concerns about my health. I'm doing great and feeling great! I'm excited to share with you all a few projects I am working on in the near future. For now, thank you all for your concerns!"

A video of a talk given by the star recently in Chengdu was also uploaded, which showed Li speaking energetically and in good spirits.

Fans all over the world have expressed shock at martial artist and celebrity Jet Li, over his recent frail appearance in a photo taken during a visit to a Tibet temple.

Wrinkled and grey, the man in the photo looked worlds apart from the characters that fans are used to seeing.

This is due to Li's hyperthyroidism and also spinal problems resulting from decades of demanding stunts on the movie sets, reported The Star and South China Morning Post.

In fact, the superstar health has been in decline since he revealed his condition to the public in 2010.

He said: "I've suffered from illnesses, for example, hyperthyroidism. I am fat but I can't lose weight because I am taking medication for my illness.

"The medication is to control my heartbeat. That's why I can't do lots of exercises."

At that time, Li also revealed that his resting heart rate was around 130 to 140 beats per minute, much faster than a normal resting heart rate which is between 60 and 100 bpm.

In response to the alarming images of Li, his manager, Steven Chasman said that it was simply a "bad photo of someone who is 55 years old".

He added that Li has been dealing with hyperthyroidism for nearly 10 years, and the condition is not life-threatening.

The Beijing-born marital artist had said that he would tackle his condition 'head-on' after he was diagnosed with hyperthyroidism.

Although treatment was successful initially, Li later suffered a relapse.

In 2013, Li also revealed that doctors warned him that he would "end up in a wheelchair" if he continued pushing his limits to make action films.

However, he said: "I'm in pain but I'm not in a wheelchair yet."

His recent appearance has many netizens questioning the condition of Li's health.

Said one netizen in Mandarin: "I can't recognise his face anymore."

Another netizen commented: "I feel really sad that you had to sacrifice your health for your movies."