The 18-year-old 'Baby' hitmaker is said that he refuses to use Auto-Tune, the popular audio processor utilised by other stars including Britney Spears, but recording studio engineers correct the pitch of his singing with Melodyne software.

"I don't use Auto-Tune. They tune my vocals - they use Melodyne. But every artist uses Melodyne. Not every artist, but 99 per cent of artists. I like the sound, the perfectness of tuning in the record. No one has completely perfect pitch," Bieber said.

Justin Bieber. Pic/AFP