Justin Bieber shows off some muscle in topless (9 PICS)

What a show off! Justin Bieber flashed some muscle during part two of NBC's fly-on-the-wall documentary All Around The World

He's been known to whip his fans into such a frenzy when he appears on stage that paramedics are called to rescue those overwhelmed by Bieber Fever.

So some might call Justin's decision to bare his chest in several topless shots during part 2 of his recent NBC documentary All Around The World somewhat irresponsible.

The 18-year-old flashed his torso and showed off his 'formidable' biceps during a behind the scenes clip from his Believe tour.

A female aide was on hand to assist the star, and thankfully appeared to withstand the effects of his exposed chest with admirable composure.

Part 2 of the documentary picked up where the previous installment had left off.

Bieber recovered having been unconscious after running into a glass wall.

His manager Scooter Braun shouted 'I can still be a millionaire!' as it was established that the young star was ok.

Aren't you astonished how buff I am? 18 year old Justin is still somewhat slender

Justin showed that he was able to think on his feet when the power went off during a secret show at the Apollo Theatre, entertaining his audience with a drum solo and leading group singalongs.

Justin also took time out from his busy tour to spend some quality time with his little sister Jazmyn.

He cuddled up to the youngster between concerts and also played with her during time spent in the car driving between hotels and concert venues. 

Brotherly love: Justin took time to hang out with his three-year-old sister Jazmyn backstage

Justin's overwhelming success has meant that he is now in a position to pick and choose which stars to collaborate with in the future- and it appears he's looking towards artists from across the pond.

According to the Mirror, Justin recently said: 'The One Direction guys are great. We have a lot of fun whenever we hang out. They came over my house and we were just chilling out around the pool and listening to music.'

'We were talking about me collaborating with them on a song on their next album. It’s gonna be great.'

'And I asked them who else they would like to work with. They were, like, Rihanna, Katy Perry, Taylor Swift and Jennifer Lopez.'

'Now don’t get me wrong those are all very talented artists but there seems to be a pattern emerging and, looking at the smile on the guys’ faces, I don’t think it was all about the music...'

Naptime: In a tender moment Justin cuddled up to his young sibling on the sofa

Made the most of his time: Justin took advantage of car and bus rides between performances to entertain Jazmyn

Are you really surprised? Justin was incredulous when he heard that he'd sold out two Madison Square Gardens concerts within 30 seconds

Connects with his fans: Justin jokingly showed off a temporary 'Belieber' tattoo

Feels blessed: Justin is always quick to thank his fans for their continued support

Where it all began: Justin makes a quick stop back at his home town, Stratford, in Canada