Twinkle Khanna's debut film production 'Padman' is a biopic on Arunachalam Muruganantham, the inventor of a low-cost sanitary pad making machine in India and the role will be played by her husband and actor, Akshay Kumar. Actress-turned-author Twinkle Khanna says she is hopeful that the film will bring a spotlight on something that has been "hidden in the darkness" for so long.