The film is an official remake of the 2011 Hollywood film 'Warrior'.
"In health there is freedom, it liberates you, you realise this after a bout of illness and then recover... now back to action 'Brothers'," Sidharth, 29, posted on twitter.
Besides Sidharth and Akshay, the film also stars Jacqueline Fernandez and Jackie Shroff.
'Brothers' will be directed by 'Agneepath' helmer Karan Malhotra and produced by Karan Johar.
The film is slated for release on October 2, 2015.