Pink Floyd - one of the biggest UK bands of all time - reunited for 2005's Live 8 concert in London's Hyde Park.
Roger Waters, Pink Floyd's bass player and main lyricist, rejoined the band he co-founded after an absence of more than 20 years.
Pink Floyd's most successful line-up - Roger Waters, David Gilmour on guitar, Rick Wright on keyboards and Nick Mason on drums - had not played together since the days of their last hit, the 1979 double concept album The Wall.
Roger Waters is rejoining the band he left in the 1980s
Since then, they have performed in depleted formations, following an acrimonious break-up and legal wrangling.
Pink Floyd, however, took the world of music by storm many years earlier, when they developed their own very original brand of rock.
In their heyday, their music combined symphonic orchestral elements with a generous and ground-breaking use of electronic and "concrete" music - clocks, planes, and other real-life sounds - as well as sharp lyrics.
Pink Floyd were formed in 1965 by four Cambridge students - Syd Barrett, Roger Waters, Rick Wright and Nick Mason. David Gilmour soon replaced Barrett, who started to suffer from mental health problems.
Some die-hard Floyd fans still believe the short-lived Barrett period to be the band's best.
SELECTED DISCOGRAPHY - ALBUMS
The Piper at the Gates of Dawn (1967)
Ummagumma (double - 1969)
Atom Heart Mother (1970)
The Dark Side of the Moon (1973)
Wish You Were Here (1975)
The Wall (double - 1979)
Others, on the other hand, particularly admire the experimental period of the late 1960s and early 1970s - which produced difficult and often brilliant works such as Ummagumma, Atom Heart Mother and Meddle.
But the band's real worldwide success came in 1973 with one of the decade's defining works, The Dark Side of the Moon, where they successfully combined the experimentalism of their early days with hi-tech electronic music and more melodic tunes.
The album also represented the first explicit foray into left-wing politics, with the band denouncing what they saw as the alienation caused by modern capitalist society.
It stayed in the US charts for a record 27 years.
Roger Waters' anti-establishment lyrics - prominent in The Dark Side of the Moon - came even more to the fore with the band's following albums, Wish You Were Here, Animals and The Wall.
Pink Floyd are also famous for their spectacular concerts
A track in The Wall album, Another Brick in the Wall Part 2, was the band's only number one single.
Its success owed much to its most original feature, a choir of North London schoolboys rebelling against their teachers.
A quarter of a century on, Pink Floyd's public profile has never been as high as it was in the late 1970s.
But the Live 8 show - with its political overtones - was a perfect vehicle for a band well known for anti-establishment views.