By Cover Media.
The singer posted a photograph showing her and a group of friends all dressed in identical purple hooded tops in honour of the teen idol.
Katy posted the picture to her Twitter account a few hours after seeing Justin in concert at the Staples Center in Los Angeles on Wednesday.
Katy displayed the picture of her wearing the heartthrob’s signature hoodie and declared she is one of the fans known collectively as the “Beliebers”.
The star claimed seeing the pop star was the perfect musical balance, as it followed her attendance at rock duo The Black Keys’ concert earlier this week.
“WE ARE BELIEBERS!” Katy tweeted excitedly.”Last night I saw The Black Keys, tonight I saw Bieber. I think my musical week is complete.”
The hugely popular star retweeted Katy’s declaration to him on his page. Katy’s public declaration of her enjoyment of Justin’s concert was mirrored by a host of other celebrities present at his concert.
These included supermodel Heidi Klum and reality TV star Khloé Kardashian who also expressed their enjoyment of Justin’s performance.