Katy Perry has opened up on what it's like to have relationships in the public eye.

The singer was married to Russell Brand before splitting in 2011, whilst she has also dated John Mayer.

Speaking to Billboard, the US star - who performed at the Super Bowl on Sunday (February 1) - said that going out with famous people is a constant learning curve.

She said: "What I will say is that to have any relationship at this level you have to just be protective and figure out how to navigate it.

"There is no handbook. In all my relationships, I've learned how I have to be more careful and that it's not up for public consumption."

Perry split from Mayer last year, but she was pictured with him at the Super Bowl in a photo posted online by Missy Elliott.

The rapper and Lenny Kravtiz were special guests at the American football event.

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Watch Katy Perry perform at the Super Bowl below: