Australian director George Miller has added to the outpouring of heartfelt messages for the late Robin Williams, saying he was "one-of-kind".
The world was rocked by the news on Tuesday morning that the beloved Williams had been found dead at his home in Tiburon, California.
Miller, who worked with Williams on the Happy Feet movies, was stunned.
"To hear of Robin's death it's almost hard to imagine because he's so utterly full of life," he said.
"He was one of a kind and he was a genius in every way."
Williams lived in Sydney while recording for Happy Feet 2, in which he played not one, but two different penguins.
Miller told of the fast-talking Williams' extraordinary ability to improvise.
"Having worked with him you get to glimpse something of how his extraordinary mind worked and you realise there's just never been anything quite like it before."
"He was someone who was breathtakingly intelligent," he said, adding that Williams observations of the world fueled the wonderful material he came up with, often on the spot.
"The fact that he's no longer able to give that to the world is really tough."
But it wasn't just Williams ability to make everyone laugh that will be missed.
"(He was) also just as a human being quite magnificent with a massive heart," Miller said.
"I must say it's a bit of a shock to talk about him as if he's no longer with us."
The internet has been flooded with devastated messages from around the world since the news broke.
Miller says he think Williams knew how much he was loved.
"He was incredibly humble but you could see the delight he had when he knew he could make people laugh," he says.
"He actually, in that way he was like a child, he would just delight in making people laugh."
But going hand-in-hand with that was that Williams was a profound thinker.
"To know someone like that was suffering from depression and so on just makes it even harder," he says.
- Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14.