Actor Shekhar Suman, who is gearing up for his debut directorial "Heartless", a tribute to his late son Aayush, says the movie will prove to be a tough challenge for his younger son, actor Adhyayan.

"Adhyayan, who was two years old, has witnessed his brother's journey, so he will be reliving his brother's life in the film. This will be the toughest role of his career, " Shekhar told.

The actor-turned-filmmaker lost his son to congenital heart disease.

Aayush was born in 1983 and Shekhar discovered about his disease in late 1990. He lost his son after four years of struggle, on July 22, 1994.

"This is one incident which has stayed in my mind for so long. For us Aayush still lives... he is still with us, " he added.

"Heartless" is Shekhar's tribute to Aayush, in whose name he has also decided to build a hospital called Aayush Memorial Hospital for Paediatric Cardiology.

"I have seen (my wife) Alka sacrifice her whole life to see him get better, and we all have, hence, lived thinking perhaps we could have done something more. But we can't change our destiny, " he added.

Shekhar says "Heartless" will go on floors in Dubai in November and will be released on Mother's Day next year.

"The film will be a mother-son relationship, a thriller and also a love story with a positive message. Deepti Naval will play the mother's role, " said Shekhar, adding that it will be an engrossing medical thriller.

"For me, it's an emotional journey. The film will be written by Nina Arora, the writer of 'Page 3', and the dialogues of the film are written by Niranjan Iyengar."

Shekhar will also have a special role in the film.