He struck up a friendship with world champion boxer Floyd Mayweather over a year ago.
And now it seems that Justin Bieber is getting more bang for his bromance, as he has now been seen training with the professional athlete.
The pint-sized pop star shared a video on his Vine account, showing him working out with the boxer at a gym on Friday.
In the six-second clip, the Canadian singer is seen lightly punching his trainer as he works up a sweat.
Showing off his lithe, muscular body, the Never Say Never star went topless in pair of long white boxing shorts and training shoes.
The two-time Grammy nominee certainly looked the part in boxing gloves, as he repeatedly threw jabs and hooks at his unflinching professional pal.
The international superstar, who has millions of dedicated fans, has clearly been working hard on his physique in recent months.
Source: Daily Mail