Justin Bieber was left open-mouthed during a gig in New Jersey on Wednesday night (31Jul13) when his manager surprised him on stage with a special award for record sales.

Scooter Braun halted the singer's concert at the Prudential Center in Newark to present Bieber with the Recording Industry Association of America's (Riaa) Diamond Award, a prize to mark 10 million U.S. sales of his hit track Baby.

Braun pointed out Bieber has managed to exceed the 12 million mark with his 2010 single, and he paid tribute to his protege in a heartfelt speech, telling the crowd, "I met Justin when he was 12, and through all the good times and all the hard times, he has stayed positive and worked hard for all of you. So it gives me great pleasure... to give you this (award) which says 'The Diamond Award is presented to Justin Bieber in recognition of Baby for 12 million sales', making Baby the number one most certified song ever in U.S. music history. Congratulations."

Bieber, 19, mouthed the word 'wow' during Braun's speech and then dedicated his award to his young fans: "First and foremost I wanna thank all my Beliebers (fans) in the audience. Second of all I want to thank all of my Beliebers at home. I wanna thank my mum... and Scooter. Thank you."

After the show, he wrote in a post on Twitter.com, "Amazing night and honoured. So much more to do. I love my Beliebers. Thank u (sic)!"

The award was a major boost to the troubled star, who has hit headlines for all the wrong reasons in recent weeks. Bieber was back in the news again earlier in the week (beg29Jul13) after police officers found marijuana on his tour bus.

He also faced a backlash from critics following his show in New Jersey on Wednesday, with a number of reviewers criticising the star for lip-syncing his set.