Los Angeles: Condolences poured in Tuesday after the shock announcement of the death of Oscar-winning US actor Robin Williams, whose body was found Monday in his residence in the San Francisco Bay Area.
Williams, who died at age 63, was suffering from depression and authorities said he might have committed suicide.
US President Barack Obama and his family were among the many who sent condolences to Williams' family, Efe news agency reported.
"He arrived in our lives as an alien - but he ended up touching every element of the human spirit. He made us laugh. He made us cry. He gave his immeasurable talent freely and generously to those who needed it most - from our troops stationed abroad to the marginalised on our own streets," said Obama in a statement.
Borrowing an extract from French writer Antoine de Saint-Exupéry, Williams' daughter Zelda posted on Twitter: "You - you alone will have the stars as no one else has them...".
"In one of the stars I shall be living. In one of them I shall be laughing. And so it will be as if all the stars were laughing, when you look at the sky at night... You - only you will have stars that can laugh", she wrote.
Robin Williams' last tweet July 31 was to congratulate Zelda upon her 25th birthday, in which he posted a photo of them when she was a child.
"Genie, you're free," said Hollywood's Academy of Motion Picture Arts and Sciences in a tweet which was heavily retweeted and included a picture from the "Aladdin" movie, in which William voiced the Genie.
Disney's CEO, Robert Iger, described Williams as "an incredible actor and comedic genius" and said he would be remembered for bringing some of the world's favourite characters to life, from his zany alien on ABC's "Mork and Mindy" to the irascible genie in Disney's "Aladdin".
"I could not be more stunned by the loss of Robin Williams, mensch, great talent, acting partner, genuine soul," fellow actor Steve Martin tweeted.
Latin-origin actress Zoe Saldana posted on Twitter: "No words can express the sadness I feel for this tragic loss. My prayers are with the Williams family. RIP Robin Williams."
John Cusack, Mandy Moore, George Takei, Mara Shriver, Shannen Doherty, Mia Farrow, Faye Dunaway and Kevin Spacey were among the artists who also turned to social networks to express their grief.
"Robin Williams, it was an honour to know you," singer Lenny Kravitz tweeted, along with a photo of him with the actor on the set of "The Butler" film in New Orleans.
"Mr. Williams visited me the first day of filming 'The Parent Trap'. I will never forget his kindness. What an enormous loss. My condolences," Lindsay Lohan said.
Zachary Quinto and Anna Kendrick chose to mourn Williams through his quotes from the 1989 film, "Dead Poets Society".
"O captain! my captain! rise up and hear the bells. rise up - for you the flag is flung - for you the bugle trills...," Quinto posted on Instagram, while Kendrick tweeted "O Captain! My Captain! Rise up and hear the bells. Rise up, for you the flag is flung, for you the bugle trills."
The Hollywood Chamber of Commerce said flowers were placed Tuesday as a tribute on Robin Williams' star on the Walk of Fame tour.
Hollywood stars paid tribute to Williams
According to eonline.com, here's what other celebrities tweeted:
John Cusack: "RIP mr Williams - beyond great talent - such a kind and lovely person."
Ben Stiller: "A tweet cannot begin to describe the hugeness of Robin Williams heart and soul and talent. This is so sad. #RobinWilliams"
Taylor Swift: "Heartbroken for Robin Williams and his family."
Ellen DeGeneres: "I can't believe the news about Robin Williams. He gave so much to so many people. I'm heartbroken."
Katy Perry: "So sad about Robin Williams...??"
Miley Cyrus: "I can't take the Robin Williams news. I've never cried over someone I've never met but I can't stop????????"
Quincy Jones: "RIP to my dear brother and friend Robin Williams. The world will miss the decades of laughter that you gave all of us."
Photos: Shraddha Kapoor, Kim Sharma at 'Haseena Parkar' screening
Mumbai to Goa train: First look at the glass-top Vistadome coach
Shuttler Ashwini Ponnappa keeps it short and sexy on social media
Photos: Narendra Modi, others at Marshal Arjan Singh's funeral
Photos: Sussanne Khan and Nimrat Kaur spotted at a spa in Juhu