Taylor Swift's 1989: What's new on Taylor's Version and why has she re-recorded it?

Taylor Swift has delighted fans with a re-recorded version of 1989, the best-selling album of her career, along with five unheard songs from those sessions.

The demand to hear "Taylor's version" of the 2014 album caused technical problems on some streaming services, Swifties reported on social media.

It's the latest in a string of re-recordings by Swift, who wants to take back ownership of her old material.

Of the extra songs, one called "Slut!" tackles her reputation at the time.