Bieber often performs acoustic versions of his hits, most recently at the American Music Awards in November, where he delivered a stripped-down version of dance song "As Long As You Love Me".

But most ears now are turned to new track "Nothing Like Us," which follows Bieber's widely reported split from former Disney Channel star Gomez.

It features Bieber singing a raw and emotion-filled ballad over a piano melody, with lyrics such as "Girl, why would you push me away?/Lost in confusion, like an illusion ... But that is the past now, we didn't last now."

SIMPLE LOVE SONGS

Bill Werde, editorial director of Billboard music magazine, who interviewed Bieber last week, said the song was "directly about Selena" and that fans were anticipating the singer sharing "his feelings about something this personal".

Werde said he hoped people would take notice of Bieber's song-writing and vocal production skills on the new album.

"Some of the best songwriters that are working out of our pop space are the ones that can take these very, very specific feelings that you would expect a teenager or a young adult to have and then sing and write about them in a way that makes them universal," Werde told Reuters.

"That's a skill that needs to be respected. It's not easy to write great, simple love songs."