Just watched this on Movies 24 (UK Cable) Loved it!
My favourite line is right at the end when he's offered the cocaine by the studio guy and he says 'Hey Robin, you want some?' and he replies 'Yes' and then walks off, brilliant! The guy playing Williams was absolutely spot on, I was dubious at first but within 5 minutes, I believed he was Williams.
I consider it unfair to enter a battle of wits when my opponent is so inadequately armed.