Katy Perry has split from John Mayer for the third time.

The "Wide Awake" singer - who broke up with him after two weeks of dating last August and again briefly in October before reconciling - has reportedly called time on her relationship with the "Half of my Heart" singer, but friends predict it might not be permanent.

A source close to the couple confirmed they recently broke up again and told UsMagazine.com, "It's sad. It's not over until it's over. You have to see how things play out." Another insider hinted that Katy might reunite with him again, saying, "She's leaving the window open. They have both been so focused on work."

Katy was previously said to have told John to lose her number because he could not commit. But he appeared to change his ways and happily began attending events with the 28-year-old brunette beauty, including the Grammy Awards last month as well as at Barack Obama's second inauguration last November. They were also spotted on several dinner dates with Katy's parents in Los Angeles and in her native Santa Barbara, where they spent Christmas together.