Rihanna steps out looking exhausted after a string of late nights out partying

No wonder she's tired! Rihanna steps out looking exhausted after a string of late nights out partying

If Rihanna was looking exhausted today, she had every reason to be.

Since touching down in the U.K last week, the 24-year-old has been partying hard.

After wrapping up her BRIT Awards celebrations at around 4am last night, most would prefer a night in.

But the Barbadian star stepped out after a string of nights out partying, but this time it appeared that her late nights were taking a toll.

Exhausted much Rihanna stepped out in London for dinner last night looking exhausted

Exhausted much Rihanna stepped out in London for dinner last night looking exhausted

The Russian Roulette singer looked downcast as she made her way to dinner at Japanese restaurant Novikov in Knightsbridge, London, for the second time in the past week.

She covered her no doubt tired eyes with some black sunglasses and could barely raise a smile as she entered the eatery.

Rihanna had just made her way from Topshop where she had spent a whopping five hours privately shopping in the popular high street store.

Short shorts: Despite earlier tweeting that she was freezing in the English capital, she stepped out in a pair of tiny Daisy Dukes

Short shorts: Despite earlier tweeting that she was freezing in the English capital, she stepped out in a pair of tiny Daisy Dukes

Short shorts: Despite earlier tweeting that she was freezing in the English capital, she stepped out in a pair of tiny Daisy Dukes

And despite earlier tweeting that she was freezing in the English capital, she stepped out in a pair of tiny Daisy Dukes.

The singer did however manage to shield her pins from the cold by slipping on some woolen tights underneath.

She paired the look with a black turtleneck top, a grey blazer and some gold sandals, and swept her blonde hair up in a bun and wore lashings of red lipstick.

Need a hand Rihanna was helped along by a friend who also carried a giant bouquet of flowers

Need a hand Rihanna was helped along by a friend who also carried a giant bouquet of flowers

Earlier today the Umbrella star had complained about the chilly London weather.

'London is cold AS F**K!!!!!!!!' she wrote on her Twitter account.

Last night Rihanna partied until the wee hours after giving an astonishing performance of her smash hit We Found Love after winning the award for International Female artist at the BRIT Awards.

Money to burn: Rihanna had just made her way from Topshop, where she had spent a whopping five hours privately shopping in the popular high street store

Money to burn: Rihanna had just made her way from
Topshop, where she had spent a whopping five hours privately shopping in
the popular high street store

She slipped into a dazzling neon dress and sunglasses to attend an afterparty at London nightclub Mahiki.

The singer completed her look with patent blue heels and opaque black ankle stockings.

The star had a red mark on her neck which looked rather like a love bite – but might equally have been a smudge of lipstick.

Party girl: Last night Rihanna partied until the wee hours after giving an astonishing performance of her smash hit We Found Love after winning the award for International Female artist at the BRIT Awards

Party girl: Last night Rihanna partied until the wee
hours after giving an astonishing performance of her smash hit We Found
Love after winning the award for International Female artist at the
BRIT Awards

Rihanna pulled out all the stops during the show, donning a plunging sequin number for the red carpet.

Love bite The star had a red mark on her neck which looked rather like a love bite - but might equally have been a smudge of lipstick

Love bite The star had a red mark on her neck which looked rather like a love bite – but might equally have been a smudge of lipstick

The star, who was on the tail end of a three-day party in London after celebrating her 24th birthday, showed off some serious skin as she posed for photographers on the red carpet.

Her gold dress had a halterneck-style which finished at her navel, and a thigh-high split showing off her enviable legs.

Later in the evening, she donned a curly wig to give an energetic performance of We Found Love after winning International Female Solo Artist, wearing just a long-sleeved top, exposing her underwear underneath.

She sang in a clear box which contained dancers splashing paint around, and later emerged with green paint on her outfit.

The star beat off competition from Beyonce, Bjork, Feist and Lady Gaga for her International Female Artist gong.

On Saturday night the Barbadian star stepped out with Chloe Green to celebrate her 24th birthday, again at Nozomi.

She looked typically striking, lurking beneath her sunglasses despite it being nightfall and sporting long gold feline talons.

Victory! Rihanna posed with her Brit Award for International Female Artist after the ceremony

Victory! Rihanna posed with her Brit Award for International Female Artist after the ceremony

Victory! Rihanna posed with her Brit Award for International Female Artist after the ceremony

Tore up the stage: Rihanna's performance was an indisputable triumph

Tore up the stage: Rihanna's performance was an indisputable triumph

Rihanna kept evey inch of flesh under wraps, but still looked effortlessly sexy and feminine in her black trouser suit and white fur coat.

Rihanna looked rather fresh-faced considering having to rehearse for the BRITs after a big night on the town.

The singer turned up to practice with the hangover from hell after kicking off her birthday celebrations early the night before.

Showing off her curves: Rihanna showed off some serious skin in this plunging gold sequin number

Showing off her curves: Rihanna showed off some serious skin in this plunging gold sequin number

Showing off her curves: Rihanna showed off some serious skin in this plunging gold sequin number

An insider exclusively 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 p***ed off like she'd been dug up.'

Rihanna even tried to incite a little sympathy from her 13.5 million Twitter followers, tweeting: 'I can't believe I'm pullin an all nighter on my BDAY!!!'

Cheers: Rihanna partied with supermodel Kate and Stella McCartney at the designer's Winter 2012 London Evening Wear Presentation last Sunday night

Cheers: Rihanna partied with supermodel Kate and Stella McCartney at the designer's Winter 2012 London Evening Wear Presentation last Sunday night