The 'Dark Horse' singer looked hot to trot in a thigh-flashing number as she took to the red carpet ahead of the charity bash in Los Angeles.
Never one to hide her a-mazing figure, Katy rocked a black Versace gown complete with a tiny miniskirt balanced with a high neckline.
Her designer dress also featured two yellow and black panels which trailed across the floor as she made her way into the event.
Gorgeous Katy accessorised with neon yellow bracelets while toting all her essentials in a white Edie Parker clutch.
She added another pop of colour with her shoes, teetering along in red and black pointed heels by Christian Louboutin.
And it's not just Katy's outfit we're loving, the songstress looked absolutely flawless on the beauty front too.
Clearly not bored of her blunt bob yet, the starlet flaunted a straight, glossy 'do which just grazed her shoulders.
Her sparkling blue peepers were decorated with feline flicks and she showcased oodles of lashes and a natural rosy pout.
And if Katy was trying to make on/off beau John Mayer jealous with her sizzling outfit, we reckon it must have worked!
Katy and John reportedly called off their relationship in February, however the 'Roar' singer has not confirmed the speculation.
If it is true, we bet John is kicking himself now!
What do you think of Katy's outfit? Let us know by commenting below as the best comment across the site each week wins £50!
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Watch Katy's 'Dark Horse' video below: