Kanye West takes a nap during fiancee Kim Kardashian's birthday bash... but ...

By Daily Mail Reporter and Jade Watkins

PUBLISHED: 10:33 EST, 26 October 2013 | UPDATED: 11:40 EST, 26 October 2013

It was his bride-to-be Kim Kardashian's 33rd birthday extravaganza on Friday night, taking place in one of the most exciting cities in the world - Las Vegas.

But it seems that all of the festivities over the last few days had finally caught up with Kanye West on Friday night.

The rapper, who proposed to the reality star earlier in the week on Monday night, appeared all tuckered out, and was snapped taking a little nap while standing up, as the couple and her famous clan hit TAO nightclub at the Venetian Hotel to celebrate Kim's milestone.

With his arms crossed, Kanye had his head down and eyes shut while he appeared to be taking a little snooze.

The 36-year-old was no doubt exhausted, after planning his lavish proposal to the Keeping Up Kardashians star and also performing in his Yeezus world tour.

Earlier in the night on Friday, Kanye had taken to the stage at the MGM Grand Hotel & Casino before heading over the The Venetian to be by Kim's side.

But one thing certainly did perk the Touch The Sky singer up, and that was the sight of his new fiancee's figure clad a very low-cut white lace crop top and matching curve-enhancing pencil skirt.

At one point, Kanye was seen staring intensely at the mother-of-one's eye-popping cleavage with his mouth agape as they walked around the casino floor.

Never one to do anything in halves, Kim went all-out for her 33rd birthday party and made the most of her eye-popping post-pregnancy figure.

The reality star was in Las Vegas four days after her actual birthday.

'Let the bday festivities begin Vega$' the Keeping Up With The Kardashians star tweeted to kick off the party, along with a photo of herself in her cleavage-enhancing white lace ensemble.

The corset-style top pushed the new mother's already large breasts up even more, as she stared demurely into the camera.

Joining the birthday girl were sisters Khloe and Kourtney Kardashian, and entourage Naya Rivera, Robin Antin, and new best friend, Blac Chyna.

While Kim's actual birthday will be hard to beat, with Kanye getting down on bended knee and proposing, nevertheless the reality star was dragging out the celebrations with her official party at Tao in Sin City.

Kim and her new fiancé arrived in Las Vegas at lunchtime on Friday and naturally the first thing that the birthday girl wanted to do was pose for a photograph.

While they were at the airport, Kim and Kanye and their group of pals, including rapper Tyga and Kim's best friend Jonathan Cheban, posed for a cool picture in front of some planes.

The gang leaned up against the bonnet of the car, but Kanye took it a step further and hopped up so that he was standing on the vehicle's hood, as Tyga crouched beside him. Kim wasn't about to attempt that in her high heeled sandals, so instead posed up in front of the car.

The blonde beauty went for a rock chick style look in a black T-shirt, skinny jeans, a gold chain choker and futuristic square black sunglasses.

Kanye, meanwhile, was wearing a red plaid shirt unbuttoned over a grey T-shirt, along with dark jeans and tan boots.

'Vegas...we've arrived!!!' an exciting Kim wrote alongside the photo as she posted it to Instagram.

It seems the couple, who attended an event in Los Angeles the previous evening, left their four-month-old daughter North West at home as they headed to Sin City.

Earlier in the week, Kim was in San Francisco where Kanye put on an elaborate proposal for her in the AT&T Park, and her family were there to watch.

The reality star, who has been married twice before, gushed that the night was 'truly magical'.

'I am the luckiest girl in the world!' she told E!. 'I get to marry my best friend!'

Meanwhile Kanye admitted in an interview prior to the lavish event that he's 'never loved a girl' as much as Kim, except for his mother, Donda West, who died in 2007 following plastic surgery complications.

'I have never loved any girl, other than my mother, as much as I love my girlfriend,' he said of Kim during an interview on Monday with San Francisco radio station KMEL.