Sharon Osbourne thinks troubled pop star Justin Bieber ''needs a good slap'' and is surrounded by people who constantly allow him to get away with his bad behaviour.

The outspoken music manager - who has managed her rock star husband Ozzy Osbourne for over 30 years - thinks the troubled pop star is surrounded by the wrong people, who constantly allow him to get away with behaving badly.

Sharon said: ''He needs a good slap. He is surrounded by the wrong people, by kiss-asses. I would say, 'Put your little ass in the studio and don't come out until you have a great body of work.' '' The candid music expert went on to dismiss the Canadian heartthrob's music as being ''floppy, poppy [and] disposable'' and thinks he needs to put out great music in order to have a ''licence to misbehave''.

The sharp-tongued star also opened up about her own life, admitting years of cosmetic surgery has left her looking like a comic book villain. She quipped to the Daily Mirror newspaper: ''A couple of years ago I looked at myself and thought, 'Oh dear, you look plastic.'

 I looked at myself being interviewed on TV - I looked like The Joker!'' Sharon, 61, has previously proclaimed the 'Confident' singer would need to go to hospital ''to get my foot out of his ass'' if she were his manager.