Her new album 25 has already sold at least 2.433 million units - the total set by 'N Sync with the release of No Strings Attached in 2000.

As a result, 25 will surge to the top of the American charts this week, toppling Justin Bieber's Purpose.

Chart experts expect 25 to top 2.9 million sales by the time the official Billboard 200 countdown is announced on Sunday (29Nov15).