Justin Bieber's manager has revealed that the singer is penning at least one song a day on average whilst on tour.

The Canadian is currently traversing the globe as he takes his Believe tour to his masses of screaming fans.

Speaking to MTV, manager Scooter Braun said that his client is most definitely in songwriting mode whilst on the road.

He said that Bieber has so many songs written that he has to group them by the city he creates them in. Braun said:

"Well I don't ever disclose what our plans are, but I will say this - he's been writing one to two songs a day for the entire tour and he actually labels them by the city he writes them in."

He continued: "We started calling it his 'music journal' and we're talking about what should come next musically. And I think creatively he just wants to share all his thoughts through music." Watch Justin Bieber perform live below: