Actor-filmmaker Rakesh Roshan, 69, has been diagnosed with early stage of squamous cell carcinoma, a type of cancer.
Indian prime minister Narendra Modi, apart from film fraternity members, prayed for his good health.
Rakesh's actor son Hrithik shared the news via social media on Tuesday morning, before his father was going in for a surgery.
"Asked my dad for a picture this morning. Knew he wouldn't miss gym on surgery day. He is probably the strongest man I know.
"Got diagnosed with early stage squamous cell carcinoma of the throat a few weeks ago, but he is in full spirits today as he proceeds to battle it. As a family we are fortunate and blessed to have a leader like him," Hrithik captioned the picture in which the father-son duo have struck the same pose.
The note drew speedy recovery and good luck wishes from Modi, the film fraternity and fans.
A post on the @narendramodi Twitter handle read: "Dear Hrithik, praying for the good health of Shri Rakesh Roshanji. He is a fighter and I am sure he will face this challenge with utmost courage."
Hrithik's former wife Sussanne Khan wrote: "He is stronger than any superhero. All will go smoothly."
Other popular names who sent in wishes include Abhishek Bachchan, Tiger Shroff, Sanjay Kapoor, Aalim Hakim, Darshan Kumar, Nandish Sandhu, Dabboo Ratnani and Vishal Dadlani.
The family has a cancer survivor in Sunaina Roshan, Hrithik's sister. She fought cervical cancer and survived it.
Apart from his acting career, Rakesh Roshan is known for directing films like "Kishen Kanhaiya", "Karan Arjun", "Kaho Naa... Pyaar Hai", "Koi... Mil Gaya" and the superhero "Krrish" film series.