John Travolta said he never knew a "sweeter, brighter, more considerate person" than Robin Williams.
In a statement the Get Shorty star said: "I've never known a sweeter, brighter, more considerate person than Robin."
He added: "Robin's commitment as an artist to lifting our mood and making us happy is compared to none..... I love you Robin."
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.