"I thought it would be appropriate to draw blood tonight... XLIX" she posted on Instagram on Sunday, alongside this shot of her getting a tattoo on her finger.
But is Katy also celebrating a reunion with ex-boyfriend John Mayer? Missy Elliott -- who Katy brought on as a special guest during the halftime show -- tweeted this photo of her posing with the on-again/off-again couple at a Super Bowl afterparty.
"After party Super Bowl with @johnmayor @katyperry," the rapper wrote.
Katy and John reportedly split in February 2014, though the two appear to be anything but done -- Mayer, 37, was the one reportedly waiting behind-the-scenes to congratulate Katy when she came off stage following her performance, Us Weekly reports.
However, the singer/songwriter isn't Katy's only ex to show her some love on her big night. Her ex-husband Russell Brand also took to Twitter in a surprising show of support.
"Super Bowl may be baffling to Brits but half time show will be amazing. Good luck KP," his sweet message read.
Super Bowl may be baffling to Brits but half time show will be amazing. Good luck KP