Sean Lock, panellist on the comedy show 8 Out Of 10 Cats for 18 series, has died at the age of 58.
The comedian, who was not widely known to be ill, died early on Wednesday after a battle with cancer.
A statement issued by his agent said: "It is with great sadness that we have to announce the death of Sean Lock. He died at home from cancer, surrounded by his family.
"Sean was one of Britain's finest comedians, his boundless creativity, lightning wit and the absurdist brilliance of his work, marked him out as a unique voice in British comedy.
"Sean was also a cherished husband and father to three children. Sean will be sorely missed by all that knew him. We kindly request that the privacy of his family and children is respected at this difficult time."
Ricky Gervais was among the first to pay tribute on Twitter, writing: "Such sad news. RIP the great Sean Lock. One of the funniest, most influential comedians of a generation. A lovely man."
A statement from Channel 4 said: "Incredibly sad to learn of the loss of one of our greatest comedians, Sean Lock. A much loved part of the C4 family he's played a huge role on the channel for over 2 decades, and we'll miss him. Our thoughts are with his family and friends."
John Bishop wrote: "I am shocked and saddened at the news of the loss of Sean Lock. He was a brilliant comedian but more importantly he was a great person on so many levels . He will be missed hugely."