Britney mimes again at birthday bash

Britney Spears tried to put her widely-criticised appearance on 'The X Factor' behind her today as she celebrated her 27th birthday with a special show on US television.

The troubled pop star continued the launch of her sixth studio album, 'Circus' - her first since her attempted comeback with 'Blackout' last year – during the tribute on ABC’s 'Good Morning America'.