Popular make-up artist Subhash Shinde says working on the upcoming biopic 'Sarbjit' is a challenging task and that he had to spend a lot of time on research.

The film is based on Sarabjit Singh, an Indian farmer who was convicted of terrorism and spying in Pakistan and was sentenced to death. He was attacked by inmates at a prison in Lahore in April 2013 and died a few days later.