Rihanna 'struggled' through her BRIT Awards rehearsals this morning, it has been reported.
The singer, who will take to the stage at tonight's ceremony, celebrated her 24th birthday last night in London.
A source told Mail Online: 'This morning, Rihanna turned up to rehearsals really, really late and kept everyone waiting.
'She didn't do any singing or dancing whatsoever. She literally stood on the stage like a zombie.'
The source added: 'She made all of her dancers, about 50 of them, dance around her and she stood looking really pissed off like she'd been dug up.'
Following her birthday celebrations, the singer tweeted fans: 'I can't believe I'm pullin an all nighter on my BDAY!!!'
The BRIT Awards 2012 will take place tonight at London's O2 Arena.
Meanwhile, Rihanna and Chris Brown have unveiled their new collaboration 'Birthday Cake' – you can listen to here.
The pair, who dated until Brown assaulted the singer in 2009, have both posted the new remixes online.
The BRIT Awards 2012: Nominations
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