The make-up team for her upcoming Vishal Bhardwaj film used her grandmother's pics as references for one of Priyanka's looks

One of Priyanka Chopra's several looks in Vishal Bhardwaj's Saat Khoon Maaf -- that of a 65-year-old woman is based on her own grandmother.

The make-up team took photos of her mother and grandmother to do a dummy test on how PC would look at the age of 65, before shooting began. A source working on the film says, "They wanted to make Priyanka look as authentic as possible. They wanted the progression of age to look as apparent in the older Chopra women."

PC's old woman character plays Naseeruddin Shah's wife in the film. The source adds, "They did a couple of images on the computer to show the natural transition from 30 to 65. Then they used her grandmother's photo to try and make her look as close to her as possible. It was a unique way of working and even Priyanka was stunned with the final result."

Special care has been taken to make sure her aged look is kept under wraps. "Vishal has banned anyone using camera mobiles on the set while shooting with PC. Her look is one of the major highlights of the film and will leave everyone stunned."