Justin Bieber has written two new songs for his completed 'Believe: Acoustic' album.

The 'Never Say Never' hitmaker took to his Twitter account last night (27.12.12) to reveal he has finished working on the stripped back version of his third studio album 'Believe' after penning two new tracks - which are rumoured to be about his on/off girlfriend Selena Gomez - for the record yesterday.

In a series of tweets, he wrote: ''finished the #BELIEVEacoustic album tonight. wrote a brand new song to finish it off that i love. 2 new songs on there. PREORDER IT NOW!! :)

''8 wasnt enough. had to write some more new ones. now im putting out 10 SONGS on #BELIEVEacoustic . Im telling u. PREORDER it now :)

''every song has a new guitar arrangement..1 w/ piano. everything feels new and #KIDRAUHL - u guys r gonna like it. PREORDER#BELIEVEacoustic

''u hyped yet? #BELIEVEacoustic . good (sic)''

The 18-year-old star's manager Scooter Braun also took to the social networking site to confirm Justin plays guitar on the acoustic album, which is set to drop on January 29.

He tweeted: ''for those asking yes @justinbieber played guitar on the acoustic album. and yes there r now 10 song not 8 because he wrote 2 new ones 2nite

''no BS when i say we are all really happy with how #BELIEVEacousticturned out as it all sounds new and organic. Think u will all love it (sic)''

#acoustic??? (sic)''