How can a 68-year-old play a 13-year-old on screen? The make-up, says Amitabh Bachchan, is king.

Speaking to Masala! magazine from Mumbai, Amitabh could not stop praising his make-up as Auro in “Paa” (pictured left), due to release on December 4.

Asked what was the biggest challenge in playing the teen, Big B said: “Auro is a 13-year-old child suffering from a genetic problem called progeria. If a 68-year-old is playing a 13-year-old, of course it involves a lot of hard work. But all artistes welcome challenges and I welcomed this opportunity to play a very different role.

“The most difficult part was getting the make-up, the face, right in a way that actually matches a case study. We did hours and hours of research, going through medical journals, to choose the right face. And then we had Oscar-winning make-up artists from Hollywood coming down to do the make-up. It would take four-five hours to put it on and another two hours to take it off!

“Of course, with make-up on, you can’t do anything – can’t eat, can’t drink, can’t move. Sitting on a chair for five hours at a stretch was certainly taxing. But the make-up was so stupendous that it gave you the energy to do your best.

“I would say 90 per cent of the performance is the credit of the make-up. The rest of it is (director) Balki’s doing. He told me how to eat, how to walk, how to talk as Auro. And then of course, I had to behave like a 13-year-old. Jump and laugh and have all the right movements. And I’m a 68-year-old!”

What was Big B like a boy in real life? Read all about in Masala! 311, hitting the shelves on November 24.