Puberty is taking its toll on Justin Bieber's live shows - the Canadian pop sensation is struggling to sing for fans because his voice is breaking.
The 16 year old, who was offered a record deal after posting videoed performances on YouTube.com, admits he often fails to hit the high notes during his concerts.
He says, "It cracks. Like every teenage boy, I'm dealing with it and I have the best vocal coach in the world. Some of the notes I hit on (hit track) Baby I can't hit anymore. We have to lower the key when I sing live."