One of her most iconic stage costumes is a bra made from fiberglass cream buns, so Katy Perry’s latest unusual fashion choice barely registers on the odd scale.

The singer wore a dress that was unzipped half way down her back as she made her way to a pre-Grammy Awards party in Hollywood.

Katy, who topped the charts with Hot or Cold, didn’t seem bothered that her dress was gaping open at the back, leaving onlookers to think it is part of the frock’s design.

Pretty in pink: Katy Perry looked cute in a 1950s style dress

Pretty in pink: Katy Perry looked cute in a 1950s style dress which she teamed with a square clutch bag

The baby pink dress featured black lace detailing down the front, and highlighted Katy’s very slim figure.

Her jet black hair had been blow dried and slightly curled, and looked shiny in the Los Angeles sunshine.

Katy carried a box-shaped clutch, and wore bright pink lipstick to the private party.

Flying solo: There was no sign of Katy's boyfriend, womanizing singer John Mayer

Flying solo: There was no sign of Katy’s boyfriend, womanizing singer John Mayer but he joined her later at Clive Davis’ pre-Grammy bash

She opted for a pair of Christian Loboutin high heels that featured see through panels on the toes, but it was the back detailing of her skin tight dress that raised the most eyebrows.

There was no sign of 28-year old Katy’s boyfriend, womanizing singer John Mayer, but he joined her later at Clive Davis’ pre-Grammy bash.

He recently opened up about his past tendency to share too much about exes.

‘I was just a jerk,’ the Born and Raised singer admits in a sit-down interview with CBS Sunday Morning, set to air on Sunday, February 10.

Unusual back: The dress featred an unusual back detailing, a zip that did not do up all the way to the top

Unusual back: The dress featred an unusual back detailing, a zip that did not do up all the way to the top

John was taking about the way he treated his celebrity ex-girlfriends, including Jennifer Aniston and Jessica Simpson.

He called the latter ‘sexual napalm’, and has previously dropped lewd hints about their active sex life.

John said to Playboy in 2006, shortly after they split: ‘Drugs aren’t good for you if you do lots of them.

‘Sexually it was crazy. That’s all I’ll say,’ he said of the Texan blonde, who he dated for a year in 2006.

‘It was like napalm, sexual napalm.’

And on Swift, 23, who went on to write a song Dear John,’ he turned to a 2012 edition of Rolling Stone to vent his spleen.

‘It made me feel terrible,’ he told the esteemed music tome, ‘because I didn’t deserve it.’

‘[Dear John is] cheap songwriting,’ he added.

‘It’s abusing your talent to rub your hands together and go, ‘Wait til he gets a load of this!’ That’s bulls–t.’

Raven haired: It's hard to believe that just a few months ago, Katy had pink, blue and purple hair

Raven haired: It’s hard to believe that just a few months ago, Katy had pink, blue and purple hair