Justin Bieber has turned his hand to rapping on new Chris Brown mixtape 'New Boy in Detention'.

The 'Never Say Never' hitmaker - who previously worked with the hip-hop star on song 'Next 2 You' - is set to feature on 'Ladies Love Me' on the collection of songs, which includes appearances by Wiz Khalifa, Swizz Beatz and Tyga.

On the track, 17-year-old singer - who appears as his alter-ego Shawty Mane - raps: "Baby I'm your doctor/ I could be your rocker/ swaggin' I'm not bargain'/ but I swear that I could rock ya'/ baby I'm not crazy/ I got swag like Patrick Swayze/ y'know them haters never phase me?that's not how my momma raised me."

Justin tweeted his fans to inform them of his rapping capabilities, write on the social networking website: "did a lil something on the upcoming @chrisbrown mixtape.. Ladies love me. then we got crazy on the @asherroth album. #shawtymane (sic)".

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