And soon later Abhiskek Bachchan's wife, the heralded actress Aishwarya Rai Bachchan, also entered hospital. The couple's daughter tested positive for Covid-19 too.
"Amitabh Bachchan is stable with mild symptoms and is currently admitted in the isolation unit of the hospital," the hospital's statement said.
On Monday, authorities in Mumbai declared Bachchan's residence in the city a containment zone. All staff members working at the residence have tested negative for Covid-19, said Vishwas Mote, an assistant commissioner at the Brihanmumbai Municipal Corporation (BMC).
Sound and Vision studio, a recording studio in Mumbai where Amitabh Bachchan's son, actor Abhishek Bachchan, had been visiting was also sanitized, according to Mote.
"We have screened all employees at the studio, nobody there showed any symptoms, we have advised everyone to home quarantine," Mote said.
A living legend in Hindi-language cinema, Bachchan has made more than 180 films in a career spanning five decades. He is hailed by many as India's greatest living actor, and is revered in his home nation.
Bachchan starred in his first film in 1969. Since then, he has dominated the silver screen for nearly half a century -- most of India's 70 years as an independent nation.
On Sunday, Amitabh Bachchan tweeted his thanks to the many well-wishers.
Tributes and well-wishes were sent to all members of the illustrious family, with Bachchan, 77, being particularly heralded on social media.
"Get well soon sir," the actor Paresh Rawal tweeted. "Praying for your speedy recovery Sir. Love and prayers," added Bollywood leading man Akshay Kumar.
The diagnoses come as India battles a devastating wave of coronavirus cases.
The country announced another 28,637 coronavirus cases on Sunday morning -- the fourth day in a row in which the country set a new daily record for infections.
India has now recorded at least 849,553 cases of Covid-19, more than any other country except Brazil or the United States. At least 22,674 people have died from the virus.
The spikes caused the city of Bengaluru to be put under lockdown for a week, starting Tuesday, to contain a massive cluster of Covid-19 cases, authorities said.