Wright (right) wrote songs on albums including Dark Side Of The Moon
Pink Floyd keyboard player and founder member Richard Wright has died, aged 65, from cancer.
Wright appeared on the group's first album, The Piper at the Gates of Dawn, in 1967 alongside lead guitarist Syd Barrett, Roger Waters and Nick Mason.
Dave Gilmour joined the band at the start of 1968 while Barrett left the group shortly afterwards.
Gilmour said: "No-one can replace Richard Wright - he was my musical partner and my friend."
Writing on his website, he added: "In the welter of arguments about who or what was Pink Floyd, Rick's enormous input was frequently forgotten."
Wright's spokesman said in a statement: "The family of Richard Wright, founder member of Pink Floyd, announce with great sadness that Richard died today after a short struggle with cancer.
"The family have asked that their privacy is respected at this difficult time."
He did not say what form of cancer the self-taught keyboard player and pianist had.
Wright, a founder member of The Pink Floyd Sound - and other previous incarnations including Sigma 6 - met Waters and Mason at architecture school.
Pink Floyd achieved legendary status with albums including 1973's The Dark Side Of The Moon, which stayed in the US album chart for more than a decade.
Wright rejoined Pink Floyd for the London Live 8 concert in 2005
Wright, known as Rick earlier in his career, wrote The Great Gig In The Sky and Us And Them from the album.
Waters left the band in 1981, performing his last concert at London's Earls Court.
Wright, together with Gilmour and Mason, continued to record and tour as Pink Floyd during the remainder of the 1980s and into the 1990s, releasing their last studio album - The Division Bell - in 1994.
In 2005, the full band reunited - for the first time in 24 years - for the Live 8 concert in London's Hyde Park.
Wright also contributed vocals and keyboards to Gilmour's 2006 solo album On An Island, while performing with his touring band in shows in Europe and the US.