Despite the stark cut, Katy looked prettier than ever in the image, which featured her heavily kohled blue eyes.
Katy, 32 - who was once married to Russell Brand and recently split from Orlando Bloom - had previously experimented with an undercut, before embracing the stylish short look.
She tweeted the image on Monday, as actor Ryan Phillippe spoke out to rubbish claims they were dating.
The 42-year-old has been heavily linked to the Roar hitmaker in recent weeks, but Ryan took to Twitter to insist that not only is he not dating Katy, he has hardly ever spoken to her in his life.
Ryan - who was married to actress Reese Witherspoon from 1999 until 2007 - wrote: 'I AM NOT DATING KATY PERRY. BARELY KNOW HER. PLEASE STOP FLYING HELICOPTERS OVER MY HOUSE. SHE IS NOT HERE.'
I AM NOT DATING KATY PERRY. BARELY KNOW HER. PLEASE STOP FLYING HELICOPTERS OVER MY HOUSE. SHE IS NOT HERE.
Ryan's statement comes shortly after Katy opened up about her sexual experiences with women.
The chart-topping singer admitted during a speech at the National Equality Award at the Human Rights Campaign Gala in Los Angeles that she had bisexual experiences in her youth.
She shared: 'I'm just a singer and songwriter, honestly. I speak my truths and I paint my fantasies into these little bite size pop songs. For instance, 'I kissed a girl and I liked it.' Truth be told, I did more than that.
'Honestly, I haven't always gotten it right but in 2008 when that song came out I knew that I started a conversation and a lot of the world seemed curious enough to sing along, too.'
Katy, 32 - who was previously married to Russell Brand and recently split from Orlando Bloom - tried to 'pray the gay away' as a teenager, but said meeting LGBT people when she got older helped to change her perspective.