Bollywood actor Irrfan Khan has revealed that he is suffering from a "rare disease".

He has asked his fans not to speculate on his condition, adding that he will share more when "further investigations come with a conclusive diagnosis".

Khan, 51, has acted in more than 100 films, including Bollywood hits Piku, Maqbool, Haasil and Paan Singh Tomar.

His English language films include Life Of Pi, Slumdog Millionaire and The Amazing Spider-Man.

He took to Twitter on Monday to talk about his illness.

Khan is India's best-known international actor and has also featured in a wide range of well-received roles in Bollywood and independent Hindi films.

🙏🏻 pic.twitter.com/JXD8NKwH3D

— Irrfan (@irrfank) March 5, 2018

In 2013, he won India's National Film Award for his leading role in Paan Singh Tomar, a biopic about a top athlete who becomes a bandit.

He has also won the Viewers' Choice Award at the Cannes Film Festival for his portrayal of a lonely accountant who mistakenly receives a lunchbox intended for a colleague in the 2013 film The Lunchbox.

It was also the only Indian film to be selected for competition at the London Film Festival that year.