Sontag: Won National Book Award in 2000

Smith, now 55, is considered to be one of the most influential female rock artists of all time.

Sontag, 69, is one of the leading intellectuals and writers in the United States.

The album, Land 1975-2002, will include previously unreleased songs, unseen photos, lyrics and artwork as well as Sontag's sleeve notes.

Fans who spoke to Smith on her tour last year and who e-mailed fan websites helped choose the tracks that will be included.

It will be released in the US on 19 March, with a tour planned to coincide.

Smith's debut 1975 album was seen as one of the seminal releases to span 60s rock and punk.

1978's Easter included her biggest commercial hit, Because the Night.

Influence

She was one of the most acclaimed performers on the New York rock scene, and was friends with Andy Warhol, Allen Ginsberg and William Burroughs.

She has influenced scores of current artists including PJ Harvey and REM.

Sontag has been described as "a living legend" and her latest novel, In America, won the National Book Award in 2000.

She caused a furore after criticising George W Bush's foreign policy and the nation's response after the 11 September attacks.