Justin Bieber is working with fellow pop star Cody Simpson on a "cool accoustic project", the Australian singer has revealed.

Canadian Biebs and Aussie Simpson both launched their careers via YouTube - and Simpson revealed they've got a collaboration in the pipeline during a chat with Hollywood Life.

"Justin and I have been in the studio for two weeks or so working on something pretty cool," he spilled.

"We're not really sure what it's going to be yet, but you'll hear something this year."

Describing it as a "real cool accoustic project", the 17-year-old added: "It might be a little more than a song."

Simpson presented JB with a "Champ of Charity" gong at the Young Hollywood Awards this week.