Teen singing sensation Justin Bieber has reportedly hired Usher’s vocal coach, to retrain his voice now puberty is beginning to hit home. According to Mr Bieber, they have already changed key on some songs to accommodate notes he can no longer hit, not that his voice is considerably deeper.

"Some of the notes I hit on 'Baby' I can't hit anymore. We have to lower the key when I sing live."

Usher had the same problem in his younger days, and it was through his mentor that Justin Bieber discovered Jan Smith, a vocal specialist. With strict orders to rest his voice as much as possible, the Canadian singer may not be talking anytime soon.

Justin Bieber is one of the many child stars that hit problems as soon as they hit puberty, and it seems to be something that plagues the male celebrity singing sensation.

According to the News of the World newspaper, Justin Bieber is developing at a slower rate than most males, and this is why at sixteen the singer is just feeling the effects of a breaking voice.

Justin Bieber was philosophical and mature about the whole process. "Everyone's voice changes, puberty is a natural thing. It cracks. Like every teenage boy, I'm dealing with it and I have the best vocal coach in the world and we're working on my voice and doing what I need to do."