Jackie Chan has reassured fans after concerns were raised about his appearance in photographs published earlier this year.

The actor and stuntman, known for films including Police Story, Rush Hour and Who Am I?, was pictured with greying hair, prompting fans to speculate about his health.

Chan has now addressed the concerns on social media, sharing a series of photos reflecting his career in celebration of his 70th birthday earlier this week.

He said his elderly appearance earlier this year was in fact part of his look for a film role.

"Not so long ago, a lot of friends saw some recent photos of me on the internet, and they were all concerned about my health," the star told his 6.2m followers on Instagram.

"I want to take this opportunity to let everyone know, don't worry! It's just a character appearance for my latest movie. The character requires me to have white hair, white beard and look old.

"Over the years, I've always been willing to try new things for a movie, no matter if it's a challenging stunt or a breakthrough appearance for a character."

Chan starred in more than 30 martial arts films in his native Hong Kong before achieving worldwide fame in Rumble In The Bronx in 1995.

He went on to star in Hollywood hits including the Rush Hour trilogy, Shanghai Noon and its sequel Shanghai Knights starring Owen Wilson, Around The World In 80 Days, and the Kung Fu Panda franchise alongside Jack Black.

The star, who is an honorary Oscar winner, did not give details of which film the ageing appearance was for. He currently has several films in production - including reprising his role as Mr Han in the next Karate Kid instalment alongside Ralph Macchio, star of the 1984 original.

In his post, he said he had cherished "every moment" of his 62 years in the entertainment industry and also spoke about turning 70, saying: "I'm 70 years old already?

"After recovering from the shock, the second thing that would come to my mind is a saying that my big brother, Sammo Hung, once said: 'Being able to grow old is a fortunate thing'.

"Especially for us stunt people, we don't know how lucky we are to be able to grow old."