Katy Perry and John Mayer split up because they were getting too serious

A source told Us Weekly: "Introducing her to his dad was a big deal. It was just too much, too soon. They've also been fighting recently."

However, friends are unsure if the split will be permanent.

The insider added: "They've broken up before so it's hard to tell. She's changed a lot since she's been with him . . . [you] can't argue that she has been in love."

John recently described their relationship as "very human" and insisted his romance with the 28-year-old singer felt totally natural.

He said: "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 know it is high profile. It's hard to explain ... For me it feels like something that's very human."

The 35-year-old guitarist also admitted he had thought about marrying Katy in the future.

When asked if marriage could be in the pair's future, John answered: "Of course. I mean, I'm still the kid from Connecticut. That's what you do."