Sammo Hung, known for his work in Hong Kong martial arts films, has come under the spotlight for his drastic weight loss.

You may also recognise him for his role in "Ip Man 2", where he challenges Ip Man to a fight.

In a Weibo post on May 25, Cantopop singer Alan Tam posted a photo of himself with 68-year-old Hung and two other friends.

They group was having lunch at Hung's house, where he had prepared a meal for them.

Tam said that the meal was delicious, but that wasn't what the fans focused on.

Instead, they were marvelling at Hung (wearing a black tee), who had grown considerably thinner.

Hung (this time in a dark red tee and a bandana) also appeared in another post that Tam had shared a few days ago on May 21.

Knee surgery in 2017

Vigorous physical activity over the years took a toll on Hung, and he had to undergo knee surgery in 2017.

After the surgery, the martial arts star was frequently spotted in a wheelchair for about two years.

His daughter-in-law Janet Chow explained that while Hung was able to walk, it's more comfortable for him to sit in a wheelchair when visiting places like a shopping mall, AsiaOne reported. 

However, he was well enough to walk across the stage at the Malaysia Golden Global Awards ceremony in 2019 to receive his Lifetime Achievement Award.

Stuntman, actor, and director

Hung has been in the Hong Kong film industry since the 1960s, and has worked as a stuntman, actor, and director, among other roles.

He has worked with many other well-known martial artists, such as Bruce Lee in the 1973 movie "Enter the Dragon" and Jackie Chan in "My Lucky Stars" in 1985.

Hung has been credited with re-inventing the martial arts genre, and even jumpstarted the kung fu vampires craze with his film "Close Encounters with the Spooky Kind" in 1980.

"Winners and Sinners" in 1983 popularised the action-comedy genre in Hong Kong martial arts films.

His most recent appearance was in 2017 historical war film "God of War":

Top Images from Alan Tam's Weibo page, Ip Man movie still