Celebrity colleagues and admirers of Robin Williams have been sharing their reactions to the comedian's death at age 63 in an apparent suicide. Here are 10 of the most eloquent and emotional tributes:

TV host and comedian Conan O'Brien, telling his studio audience:

  • "This is unusual and upsetting, but we got some news during the show that Robin Williams has passed away.... I'm sorry to anyone in our studio audience that I'm breaking this news. This is absolutely shocking and horrifying and so upsetting on every level."

Comedian Marc Maron, on his WTF podcast:

  • "He was sensitive, he was perceptive, he was empathetic, his mental agility was astounding, he was full of love, and he, by nature of putting all those out into the world, required that of us. And we felt it.… The spirit of pure comedy ran through this guy."

Nathan Lane, The Birdcage co-star

  • "What I will always remember about Robin, perhaps even more than his comic genius, extraordinary talent and astounding intellect, was his huge heart — his tremendous kindness, generosity and compassion as an acting partner, colleague and fellow traveller in a difficult world."

Actor-comedian Chevy Chase:

  • "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."

Chris Columbus, Mrs. Doubtfire and Bicentennial Man director:

  • "His performances were unlike anything any of us had ever seen, they came from some spiritual and otherworldly place. He truly was one of the few people who deserved the title of 'genius.'"

'He made such a big impact on the world'

Robin Williams Ben Stiller

Actor Ben Stiller appears with Robin Williams in 2009. (Robert Giroux/Reuters)

Ben Stiller, Night at the Museum co-star

  • "He made many, many film crews laugh out loud before the audiences ever saw it. He made such a big impact on the world."

Actor Mel Gibson:

  • "He was very compassionate. But he was also like a benchmark. And what he did — he did what he did the best. And he set a very high benchmark for people to follow. Not only did he excel in that field, but he crossed over into all sorts of other fields as well."

Harvey Fierstein, Mrs. Doubtfire co-star:

  • "Robin was friend, boss, brother, inspiration. His generosity and intelligence knew no limits. Only his home planet could destroy him." 

John Cusack,The Butler co-star

  • "A big, tenacious, overflowing, hyperkinetic eruption of compassion would be [the] best tribute to Williams." 

U.S. President Barack Obama:

  • "Robin Williams was an airman, a doctor, a genie, a nanny, a president, a professor, a bangarang Peter Pan, and everything in between. But he was one of a kind. He arrived in our lives as an alien — but he ended up touching every element of the human spirit."

With files from CBC News