Fellow comics Lee Mack, Alan Davies and Richard Osman pay tribute to the star, who leaves behind wife Anoushka Nara Giltsoff and their three childrenComedian Sean Lock - best known for panel shows 8 Out Of 10 Cats and 8 Out Of 10 Cats Does Countdown - has died aged 58, his agent has said.
A statement from his agent Off The Kerb Productions said Lock, also known for starring in the sitcom 15 Storeys High, died from cancer.
"It is with great sadness that we have to announce the death of Sean Lock," it said. "He died at home from cancer, surrounded by his family."
The statement added: "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."
Stars in the world of entertainment have been paying tribute to Lock, including his friend, the comedian Lee Mack, who said: "I've known this day was coming for some time, but it's no less heartbreaking.
"A true original both in comedy and life. I will miss him so much."
John Bishop described Lock as a "great person" and Bill Bailey said he was a "wonderful" comic.
"It's heartbreaking to lose my dearest friend Sean Lock, he was a true original, a wonderful comic. All my thoughts are with his family," Bailey tweeted.
The TV star, who was known for his surreal content and deadpan style, has been a team captain on Jimmy Carr's comedy panel shows since 2005.
He was one of the team captains for the first 18 years, alongside host Carr, Jason Manford and Jon Richardson.
Lock left the show in 2015 and was replaced by Rob Beckett.
He was born in Woking, Surrey, and began working on building sites in the early 1980s but developed skin cancer which he blamed on over-exposure to the sun.
He made a full recovery and focused on a career in comedy.
His early professional TV appearances were in 1993, starring alongside Rob Newman and David Baddiel in Newman And Baddiel In Pieces.
In 1998, he script-edited Is It Bill Bailey? on BBC Two and had his own show called 15 Minutes Of Misery on BBC Radio 4, which later expanded into 15 Storeys High.
The show was set in a tower block and centred on a pessimistic character called Vince (played by Lock) and his flatmate Errol, played by Benedict Wong.
Lock also appeared on panel shows including Have I Got News for You, QI, and They Think It's All Over.
Fellow comedians, Richard Osman, Eddie Izzard and Davies also paid tribute to Lock on Twitter.
Osman described Lock as a "unique and brilliant comic voice", Izzard said he "brought a wonderful comedic talent to the world" and Davies, who met Lock at the start of their careers in 1988, said he was "funny on stage, hilarious off".