Megastar Amitabh Bachchan and his son, actor Abhishek Bachchan, who were admitted to a hospital here after testing positive for COVID-19, are responding well" to the treatment, hospital sources said on Tuesday.

Amitabh, 77, and Abhishek, 44, revealed their diagnosis on Twitter on July 11, saying they were in the isolation ward of Nanavati Hospital.

"Both are stable and are responding well to the treatment. They will have to be in the hospital for at least seven days," the hospital insider told PTI.

Apart from the father-son duo, the screen icon's daughter-in-law, actor Aishwarya Rai Bachchan, 46, and eight-year-old granddaughter Aaradhya Bachchan also tested positive for COVID-19.

Abhishek confirmed Aishwarya and Aaradhya's diagnosis on the microblogging site on Sunday, adding that they will be "self-quarantining at home".

On Monday night, Amitabh thanked his fans and well-wishers for brightening the darkness of his isolation with their messages of love.

"The heavy rainfall of your prayers and good wishes has broken all the dams of affectionate bonds. I am flooded with so much love. I can't explain the way you have brightened the darkness of my isolation," he wrote in Hindi on Twitter.

"I bow down to you," Amitabh added

Post the actors' diagnosis, 26 staff members working at their bungalows were also tested for COVID-19. On Monday, Vishwas Mote, assistant municipal commissioner, K West ward, said all the staff members tested negative for the virus.

With 1,174 new COVID-19 cases being recorded on Sunday, Mumbai's case count has mounted to 93,894, the Brihanmumbai Municipal Corporation (BMC) said.