Katy Perry and John Mayer, who have dated on and off since last summer, have reportedly called it quits again.

Perry and Mayer first split last August after a short time dating, only to rekindle the relationship in September. Since then, the pair has been spotted looking happy together, including at the Grammy Awards in February.

"It's sad," a friend of the couple told Us Weekly. "It's not over until it's over," another source told the magazine. "You have to see how things play out. She's leaving the window open. They have both been so focused on work."

Currently, Perry has been dedicating much of her time in the studio recording her third LP. Mayer, on the other hand, is gearing up for a new tour that will kick off once he recovers from a surgery to repair a granuloma in his throat, according to Rolling Stone.

Mayer said in January during an interview on 60 Minutes, “I’m very happy in all aspects of my life.” And as recent as March 2, Perry was singing his praises on Twitter. ”My boyfriend is taking me to a kitten shelter in his truck,” she wrote. “I can’t think of a more perfect Sunday." Although neither of them has outright confirmed the split, another look at Perry’s Twitter account indicates the rumors might just be true.

"ATTENTION: Mercury is OUT of retrograde today,” Perry tweeted, hinting at trouble, on Monday. “Thank GOD.”

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