Mrs Doubtfire director Chris Columbus said Robin Williams was "truly one of the few people who deserved the title of 'genius'."
He said: "We have lost one of our most inspired and gifted comic minds, as well as one of this generation's greatest actors.
"To watch Robin work, was a magical and special privilege. His performances were unlike anything any of us had ever seen, they came from some spiritual and otherworldly place."
Sally Field, who played Williams' wife in the hit movie, added she was "stunned and so sad" about Robin's death.
"He always lit up when he was able to make people laugh, and he made them laugh his whole life long, tirelessly. He was one of a kind. There will not be another. Please God, let him now rest in peace," she said.
Robin Williams' daughter has left social media after receiving abusive messages in the wake of her father's death.
Radio station talkSPORT has apologised after presenter Alan Brazil said he lacked sympathy for actor Robin Williams, who took his own life.
He played a wide range of roles but Robin Williams captured the hearts of millions with his performances.