Justin Bieber - Justin Bieber Stuns Fans With Mobile Sing-a-long

The teenage sensation was preparing for appearance on the Jay Leno show when he stunned fans queuing outside the venue with his arrival. After the doors of the blacked out vehicle swung open, a denim-wearing Bieber began serenading the fans with the help of an acoustic guitarist. The singer treated fans to a version of his latest single 'Boyfriend', and the eager followers were only too happy to provide the backing vocals. The performance probably led Bieber to recall his days busking on the streets of his hometown in Canada, which has a population of just 30,000. Nowadays, the star has millions of fans worldwide and an astonishing 24 million 'Beliebers' following his every move on Twitter. In a recent tweet, Bieber thanked those fans for their continued support, saying, "From a town of 30,000 - on my 18th bday we hit 18 Million...and now 4 months later we are at 24 Million Beliebers!!! Teambieber Goes Hard!".

It's been an eventful couple of months for Justin, who's been promoting his latest album 'Believe', which topped the Billboard 200 this week. A recent European jaunt saw a state of emergency almost called in Norway.