Spears has scored US chart success with her new single Gimme More

The CD, Blackout, will now be available two weeks ahead of schedule on 29 October, or 30 October in the US.

Jive Records is doing "everything possible" to prevent further illegal distribution of the songs, it said.

Meanwhile, Spears' lawyers have filed an emergency court motion seeking to expand visitation rights with her two sons after she lost custody last week.

Chart hit

Spears, 25, was ordered to temporarily surrender custody of Sean Preston, two, and Jayden James, one, to her former husband Kevin Federline.

A further custody hearing has been set for 26 October, in Los Angeles.

A day earlier, Spears is required to appear in court to face charges of hit-and-run and driving without a valid licence, stemming from an incident on 6 August, when she allegedly crashed her car into a parked vehicle.

Spears' new song, Gimme More - the first single from Blackout - is rising on the US music charts, jumping from number 68 to number 3 on Billboard's Hot 100 last week.