Bieber's trying to bulk up! Justin flexes what muscles he has as he posts topless Twitter snap

He is currently on tour and it seem the performing is taking its toll on Justin Bieber's body, in a good way.  The 18-year-old singer seems to be putting on a bit of muscle and seemed so pleased with his efforts he posted a topless snap of himself to his Twitter page. Justin appeared to be trying to tense what muscles he has and some definition could be seen across his abdominal area.

Someone trying to bulk up? Justin Bieber tweeted this topless snap of himself to his Instagram page

The heartthrob had his tracksuit bottoms slung below his hips and his white boxers were visible.
While Justin took centre stage in the snap a pal was seen standing behind him looking into the mirror.
Along with the photo Justin tweeted: 'Me and @nickdemoura dance rehearsal get ready #watchout'
In September the Canadian singer began his Believe tour which will see him play gigs across North America, Europe, Africa, and Asia.
Justin will be performing more than 80 shows and will not finish the tour until May next year.
Earlier this month Bieber unveiled a large inking of an owl on his left forearm.

Show off! As well as flaunting his topless body, he was seen showing off his new tattoo

This is the second tattoo Justin has obtained in a matter of weeks.
At the start of last month he revealed a crown design on his upper chest on the right side on his Twitter page.
Justin underwent his first inking of a bird on his hip at the tender age of 16, and followed it with the Hebrew word for Jesus on his ribcage when he and his dad opted to get matching tattoos during a trip to Israel.
Adding to his collection of religious tattoos, the Canadian singer later had an image of Jesus etched onto his left leg.
In March Justin had a praying hand inking etched onto his leg, which is thought to represent the power of prayer and the Almighty. 
And in July he debuted a tattoo on his right arm - the Japanese Kanji symbol for music.