Rihanna celebrates her 24th birthday in style

The singer hit the town in Knightsbridge to toast her birthday

Rihanna stepped out in London last night to celebrate her 24th birthday, and still managed to look flawless despite pulling an all nighter the day before.

The singer headed to Japanese restaurant Nozomi in Knightsbridge and was joined by Topshop heiress Chloe Green and, rather surprisingly, Kelly Brook.

Her birthday celebrations come just a day after the star partied all night at Stella McCartney's ultra-glam after show dinner, alongside the likes of Kate Moss and Alexa Chung.

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The following morning, RiRi had to attend rehearsals for tonight's Brit Awards but apparently wasn't quite on top form.

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A source told the 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.'

'She made all of her dancers, about 50 of them, dance around her and she stood looking really p***ed off like she'd been dug up.'

We feel your pain, RiRi.

Something that did seem to cheer the 24-year-old up was a special birthday tweet from her ex-boyfriend, Chris Brown. She re-posted his message, which read: 'Thanks! RT @chrisbrown: HAPPY BIRTHDAY ROBYN!'

The pair's friendly messages come after it was revealed the stars have collaborated on a couple of upcoming songs - Brown is on a remix of Rihanna's Birthday Cake while she's on a version of his track Turn up the Music.

He is still serving five years' probation after assaulting Rihanna back in 2009.

Happy birthday from everyone at Marie Claire, RiRi!

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