Rare footage of Robin Williams has surfaced. Of course it's brilliant.

Watch Robin Williams drive this director crazy with his brilliant – but time-consuming – improvising.

He really was a genius.

Rare footage has surfaced of Robin Williams doing what he did best: Standing on stage and saying whatever came into his head.

The 13 minute clip was made to promote a director friend of Robin’s, the joke being:

“If he can direct this guy, he can direct anybody”:

Obviously the whole clip is a comedy bit, but, damn, was Robin Williams a master improviser.