KATY PERRY And Her Sweet Rack!

Katy Perry causes a sensation as she flaunts her breasts in plunging dress at the Grammys

She missed out on a Grammy, but Katy Perry still caused one of the biggest sensations of the night.

The brunette singer's mint green Gucci dress featured a keyhole cut-out that showed off her gravity defying curves.

It quickly caused excitement online as the singer's fans expressed their admiration on Twitter.

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Flaunting her assets: Katy Perry covers up her arms and legs on the Grammys red carpet but shows off her breasts in a cut out dress

Now that's impressive! Elton John appears to admire Katy's breasts

Taking a twirl: The daring dress looked great on Katy from every angle as she heated up the red carpet

And it wasn't just those at home who noticed.

Amusing photographs from inside the venue showed her fellow stars attempting but failing to avoid staring at Katy's breasts.

Even Elton John was caught out cheekily eyeing up Katy, while TV presenter Ellen Degeneres made a joke of the unmissable subject.

Cheeky grin: Elton had a bug smile as he went in for a hug off the singer

Wowser! Portia de Rossi and actress Ellen DeGeneres react with shock to Katy's plunging dress

Say cheese: Portia was ready for her photograph, but Ellen was far too distracted

'I was inspired by Priscilla Presley in the Seventies... Married to Elvis Presley, of course,' she told Ryan Seacrest on E!

Ryan joked that he had luckily had a lot of practice at staying focused when at that eye level.  

One person who managed to avoid staring was her supportive boyfriend John Mayer, who instead stared straight into Katy's eyes as the pair cuddled up inside.

Don't look down! Proud boyfriend John Mayer makes every effort not to eye up his girlfriend's breasts

She's my girl: The pair held hands and kept close to one another

Practiced posers: The on/off again couple seem to be firmly together

Lifting the lid: Mayer said at the ceremony that his relationship with Katy felt 'very human'

Sat side by side, their hands clutched firmly, the pair were the picture of a loving couple.

It comes as Mayer said his relationship with Katy felt 'very human'. 

The musician insists his romance with the Firework singer feels totally natural whereas he felt he was part of a celebrity circus with some of his previous partners. 

In an interview with CBS Sunday Morning, he said: 'I don't feel like I'm in a celebrity relationship. For the first time in my life I don't feel like I'm in a celebrity relationship. I know it is high profile. 

'It's hard to explain ... For me it feels like something that's very human.'

Impressive: Katy stands tall on the red carpet before presenting the gong

Confident display: Katy stands with hands on hips as she faces the cameras

The 35-year-old guitarist also admitted he has been thinking about marrying Katy, 28, in the future. 

When asked if marriage could be in the pair's future, John answered: 'Of course. I mean, I'm still the kid from Connecticut. That's what you do.'

Meanwhile Katy's daring dress may have been revealing but it did comply with a memo from bosses at CBS, which screened the awards.

A Wardrobe Advisory warned that body exposure would not be tolerated at the event.  

The requirements specifically instruction to 'avoid sheer see-through clothing that could possibly expose female breast nipples.'

The 55th Annual Grammys airs on 4Music at 10pm on Monday.

Behind the scene: Katy seen in another picture, here backstage at the ceremony

Be my date: Katy posing with Girls actress Allison Williams inside the ceremony

Ready for her close-up: Katy stands on the red carpet in front of the army of photographers

Outfit change: After drawing attention to her chest Katy then changed to attend an afterparty

Fun night: Singer Miguel joined Katy and John to party hard after the ceremony