Since "Brothers" is an emotional story about two siblings, Sidharth wanted to share the first look of the film with his real life brother for his feedback, said a source close to the 30-year-old.
Sidharth will be seen essaying the role of a wrestler in the film.
The movie's director played an integral role in Sidharth's transformation for the role.
"I was obsessing about my look throughout, constantly pestering Karan Malhotra, and he also helped me... showed me pictures of bulky wrestlers to get the right appearance.
"A team arrived in India all the way from the US to teach us various forms of fighting. Karan sir wanted us to balance our weights, so when Akshay sir lost 10 kg, I had to gain 10 kg," Sidharth said at the trailer launch, which happened earlier this week.
"Brothers" is an action-drama film, directed by Karan Malhotra. It is an official remake of the 2011 Hollywood film "Warrior", and it also features actress Jacqueline Fernandez in lead role, while actor Jackie Shroff will play a supporting role.
The film is scheduled to release on August 14.
Sidharth is currently filming "Kapoor and Sons" which also features actors Alia Bhatt and Fawad Khan.