Uh-oh, here we go again…

Katie Perry isn’t one to hold back when it comes to saying what she thinks – remember that time she called Taylor Swift ‘Regina George in sheep’s clothing‘ on Twitter?

Ouch.

Well now fans are convinced the California Girls singer has got a lil’ bit of Bad Blood with another princess of pop after Katy seemed to take a swipe at Britney Spears.

While chatting to Ryan Seacrest at the Grammy Awards, talk soon turned to her three-year break from music after releasing her last album Prism in 2014.

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‘There was a pause in the music for a little while,’ Ryan said.

To which Katy replied: ‘Yeah that’s called taking care of your mental health.’

When he asked how that went, she joked: ‘Fantastic! And I haven’t shaved my head yet,’ which many fans have taken as a swipe at Britney’s mental breakdown in 2007 which led to the star shaving her hair off.

Katy Perry got some Britney fans a little worked up… (Photo by Jim Smeal/BEI/Shutterstock)

Although the subject was swiftly dropped, Katy then went on to mention the head shaving reference again during an interview with CBS.

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Which didn’t go down too well with Britney’s loyal followers – and there are A LOT of them.

One fan wrote: ‘OK FINE I turned on the Grammys and Katy Perry was making a snide ‘Britney breakdown head-shaving’ reference & I’m not down with that.’

Another said: ‘I love Katy Perry and her performance was awesome and powerful but she should not have made the joke about Britney on the red carpet.’

While a third angrily wrote: ‘I just lost all my respect for Katy Perry, well the litle respect I did have for her.’

A #KatyPerryIsOver hashtag even started trending on Twitter… Blimey!

But while some fans demanded the 32-year-old apologised to Brit ASAP, Katy’s legion of followers were quick to defend the star, with one pointing out: ‘If people paid attention they would realise how much @katyperry loves Britney so all this bull s*** is boring.’

Fair enough.

Hopefully Brit isn’t too offended by Katy’s comments because we’re not sure we can handle another pop star feud!