Madonna's preview of her new song has allegedly flopped. Partygoers at the 'Pop Rocks' party at New York's Club 13 cheered when it was announced they would hear an advanced copy of the new Madonna track from her forthcoming album, but were disappointed, claiming it was too similar to Britney Spears' 'Slave 4 U'.

A source said of the song which was produced by Pharrell Williams: "Everyone cheered and was excited, but when it started playing, few were dancing."