The 'Firework' singer was photographed wearing a heart-shaped ring during a Valentine's Day dinner with Mayer.
A source told The Sun: "Katy has never been happier. She's in a really good place with John. Katy's parents also really like John. They prefer him over [ex-husband] Russell [Brand]. They thought Russell was too temperamental."
Mayer recently said of the relationship: "I don't feel like I'm in a celebrity relationship. For the first time in my life, I don't feel like I'm in a celebrity relationship, I really don't.
"I'm not in a high-profile - I know it's high-profile, it's hard to explain. It doesn't feel that way to me - and great."
Perry got divorced from Russell Brand at the end of 2011.
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