In May, Roy, who was undergoing dialysis, had asked for financial help on social media when he was admitted to the intensive care unit of a hospital here.
According to Thapar, who worked with the actor on the serial "Rishta Sajhedari Ka", Roy complained of breathlessness before collapsing in the wee hours of Tuesday.
"His staff, who was with him, offered him tea but he refused and started breathing heavily. Then suddenly he collapsed around 3.45 am. He had a kidney ailment and was undergoing regular dialysis too," Thapar told PTI.
According to Roy's caretaker, the actor's condition had significantly improved over the last few months, Thapar said.
Post his hospitalisation, the actor said, Roy had started getting work and had even dubbed for a film last week.
The late actor's sister is now en route from Kolkata to Mumbai and would reach the city in the evening, post which a decision on the last rites will be taken.
Roy, who was active in the entertainment industry since the late 1990s, had worked in films such as Emraan Hashmi-starrer "Raja Natwarlal" and "MP3: Mera Pehla Pehla Pyaar".
On the small screen, he also featured in shows like "Banegi Apni Baat", "Remix", "Kuch Rang Pyar Ke Aise Bhi" and "Jeannie Aur Juju".
Celeb Deaths Of 2019: India Lost Sushma-Jaitley, Kushal Punjabi, CCD Boss
The Final Goodbye
2019 has left a void in our hearts.
From Bollywood veterans and Hollywood celebrities to political stalwarts, we lost several personalities over the span of one year.
While big names like politicians Arun Jaitley, Sushma Swaraj and fashion designer Karl Lagerfeld lost their lives after battling prolonged illnesses, others like businessman VG Siddhartha and actor Kushal Punjabi succumbed to their mental health struggles.
Here's a look at all the influential figures we bid adieu to this year, but they continue to stay in our hearts.