Bollywood superstar Amitabh Bachchan and his son have both tested positive for coronavirus and have been admitted to hospital in India.

The Nanavati Super Speciality Hospital in Mumbai said the 77-year-old actor is stable with mild symptoms and is currently in an isolation unit.

Bachchan said in a tweet on Saturday that he had tested positive and appealed to those who were in close proximity to him in the past 10 days to get themselves tested.

His son, Abhishek Bachchan tweeted on Saturday night that he had also tested positive for Covid-19 and is in hospital.

“Both of us having mild symptoms have been admitted to the hospital,” the 44-year-old wrote. “I request all to stay calm and not panic.”

Abhishek Bachchan tweeted on Sunday that his wife, Aishwarya Rai Bachchan, and their eight-year-old daughter had also tested positive.

Aishwarya Rai Bachchan is a top Bollywood actress.

“They will be self-quarantining at home,” he said.

Maharashtra state Health Minister Rajesh Tope said Aishwarya Rai Bachchan and her daughter are asymptomatic.

Mr Tope did not say whether they were quarantined at home or were also in hospital.

Amitabh Bachchan has acted in more than 200 Indian films over the past five decades. He is also a former politician and a television host.

The Bachchans are often called Bollywood’s first family.

His wife, Jaya, is also an actress and a one-time member of Parliament.

Their son, Abhishek, and daughter-in-law, Aishwarya Rai Bachchan, are also Bollywood superstars.

The Press Trust of India news agency cited Mr Tope as saying that Amitabh Bachchan and his son have a cough and fever.

“They underwent rapid antigen test and (results) came positive,” he said.

Since Amitabh Bachchan is comorbid, he got himself admitted to hospital, the minister said.

The elder Bachchan’s breakthrough performance came in the 1973 film Zanjeer, or The Chain, and he rose to superstardom playing bold characters, inspiring fans to copy his hairstyle, clothes and deep voice.

He briefly entered politics in 1985 but resigned his seat in Parliament mid-term when former prime minister Rajiv Gandhi’s administration became ensnared in corruption.

Virus Outbreak India Amitabh Bachchan
A civic worker sanitises the gate of Bollywood superstar Amitabh Bachchan’s residence after the actor and his son tested positive for coronavirus and were admitted to hospital in Mumbai (Rafiq Maqbool/AP)

He returned to film in the 1990s and made a rare Hollywood film appearance in Baz Luhrmann’s 2013 version of The Great Gatsby.

He embraced social media, engaging with fans using Twitter and Tumblr, and served as host of Kaun Banega Crorepati, India’s version of Who Wants To Be A Millionaire?

In 2015, the actor revealed that he had been treated for Hepatitis B for more than two decades and lost more than 75% of his liver to the disease.

Mumbai, New Delhi, Chennai, Pune and Bangalore are among the Indian cities worst hit by coronavirus.

Bollywood actor Amitabh Bachchan in 2013 (Tsering Topgyal/AP)

On Sunday, India’s coronavirus caseload reached almost 850,000, with the biggest spike of 28,637 in the past 24 hours. The new confirmed cases took the national total to 849,553.

The number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling ill.

For most people, Covid-19 causes mild or moderate symptoms, such as fever and cough, which clear up in two to three weeks. For some – especially older adults and people with existing health problems – it can cause more severe illness, including pneumonia, and death.