Lil' Wayne's collaboration with Eminem, which appears on his new album 'Rebirth', has leaked online.

The track, entitled 'Drop The World', began to emerge on file-sharing websites on Tuesday.

The leak came as 500 copies of 'Rebirth' were incorrectly shipped to Amazon customers who had pre-ordered the album.

The LPs were dispatched a week ahead of the album's old release date of December 21, which has since been revised to February 1, 2010.

According to Billboard, roughly one millions copies of 'Rebirth' were shipped to retailers last month, before the decision was taken to delay the album until next year.

'Rebirth', Lil' Wayne's first rock-rap album, has been hit by a series of setbacks since it was initially scheduled for release last April.

The new release date means it will arrive in shops just a week before the rapper is due to be sentenced for gun possession.

Lil' Wayne is expected to receive a one-year jail term after entering a plea deal at a court hearing in New York last month.

(by Jason Gregory)