Emraan has penned the book 'The Kiss of Life: How a superhero and my son defeated cancer' which talks about his family's struggle with his son Ayaan's cancer treatment.
While posting a photograph of his copy of the book on Twitter on Tuesday, Hrithik wrote: "Strong father. Stronger son. And now they have the power to inspire the world. Emraan Hashmi bravo to both you heroes! Love."
Ayaan is Emraan and his wife Parveen Shahani's first child. He was diagnosed with first stage cancer at the age of four in early 2014.
Hrithik also is father of two sons Hrehaan and Hridhaan, who he has with his former wife Sussanne Khan.