The news of actor and comedian Robin Williams' death at age 63 has sent shockwaves across the Twittersphere, as friends, colleagues and admirers mourned his loss.
Williams' fellow comic-turned-actor Steve Martin summed up the feelings of the Oscar-winner's friends and fans in a tweet.
"I could not be more stunned by the loss of Robin Williams, mensch, great talent, acting partner, genuine soul," he wrote.
Ellen DeGeneres echoed that sentiment. "I can’t believe the news about Robin Williams. He gave so much to so many people. I’m heartbroken," she tweeted.
Williams' "Mork and Mindy" co-star Pam Dawber said: "I am completely and totally devastated. What more can be said?!"
“Everyone remembers him as a brilliant comedian but he was much more than that," Joan Rivers said in a statement. "He was a extraordinary actor and very generous in spirit. I cannot remember a time that we were together that he didn't make me genuinely laugh. He was one of the nice guys. I wish I had been closer to tell him what I learned the hard way...that suicide is a permanent solution to a temporary unhappiness. I really really liked him. It makes me very very sad.”
Chevy Chase said in a statement that he also suffered from depression. "Robin and I were great friends, suffering from the same little-known disease: depression. I never could have expected this ending to his life, and to ours with him. God bless him and God bless us all for his LIFE! I cannot believe this. I am overwhelmed with grief. What a wonderful man/boy and what a tremendous talent in the most important art of any time - comedy! I loved him."
Comedian Joel McHale hailed Williams as an inspiration. "You were one of the very best that ever was. You were one of my heroes," he tweeted.
Late-night star Jay Leno cited his connection to Williams that dated back to early in his career. “I saw him on stage that very first time he auditioned at the Improv in Los Angeles, and we have been friends ever since. It’s a very sad day,” Leno said.
Steven Spielberg said Williams was a “lightning storm of comic genius and our laughter was the thunder that sustained him. He was a pal and I can't believe he's gone.”
Actress Anna Kendrick tweeted a couplet from a Walt Whitman poem Williams himself had made famous in his role as an inspiring, and provocative, prep school teacher in "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."
Read more of how social media is remembering Williams below.