BB-8's creators on smashing it on set: 'It was as if someone had been hurt'

It may be the droid that launched a thousand merchandising opportunities, but BB-8 started life humbly: on a napkin.

In 2013, long before shooting the film and even before the cast had been announced, the plucky robot was born.

Out of the mind of director J.J Abrams came a rudimentary sketch, a ball on top of a ball; clearly an astromech akin to the beloved R2-D2, but different. Simple, spherical -- even revolutionary.

J.J. Abrams' sketch of BB-8 from 2013.

The crude napkin doodle was enough to pique the interest of Lucasfilm concept designer Christian Alzmann, who -- along with Neal Scanlan, head of creatures and robots on the film -- got the ball rolling on what became BB-8, the tiny star of "Star Wars Episode VII: The Force Awakens."

It was a project shrouded in secrecy, misdirection and non-disclosure agreements, but after a long enforced silence the men who made BB-8 have finally spoken about their mission to bring the Resistance droid to the silver screen.