By Nupur Anand

MUMBAI, July 12 (Reuters) - India's most famous film starAmitabh Bachchan, and his son Abhishek, are in stable conditionafter testing positive for the coronavirus, a hospital officialand government health authorities said on Sunday.

The 77-year-old legendary actor said in a tweet on Saturdaynight that he had tested positive for the highly infectiousvirus.

Within minutes, his actor son Abhishek Bachchan, 44, tweeted that he had also tested positive.

Both were moved to the Nanavati Hospital in Mumbai despiteshowing only mild symptoms and the father-son duo appealed totheir millions of fans to stay calm.

On Sunday, an official at Nanavati and government healthofficials in Mumbai said both the father and son were in stablecondition. Reports were awaited on the condition of AmitabhBachchan's wife Jaya and Abhishek's wife Aishwarya, both alsohighly regarded actors.

Meanwhile civic authorities launched a massive sanitisingdrill at Bachchan's upscale residence in Mumbai, spraying disinfectant in the large compound and on cars parked there.

A Bollywood legend, Amitabh Bachchan has been a prominentfigure in the fight against the coronavirus by appearing inpublic service advertisements in which he urges people to wear amask, wash hands frequently and maintain social distance in histrademark baritone.

India's film industry recently resumed film shoots after amonths-long hiatus following the imposition of a nationwidelockdown in late March.

But actors over 65, such as Amitabh, are banned from thesets because of their vulnerability to the virus.

Coronavirus cases have been rising steadily in India. Thedisease has infected over 820,000 people and killed over 22,000in the country, according to a Reuters tally.

(Reporting by Nupur Anand and Shilpa Jamkhandikar; Editing byRupam Jain, Raju Gopalkrishnan) ((Nupur.Anand@thomsonreuters.com; +9122 68414388;))