"Part of Me" singer Katy Perry has her friends and apparently her ex-husband British comedian Russell Brand worried with the fact that she is currently dating John Mayer. Her friends seem to be concerned with Katy Perry's rebound relationship with John Mayer that could lead to another potential heartbreak for the beautiful singer.

While things look like heating up between Katy Perry and John Mayer, most of Katy Perry's inner circle of friends is actually worried about the "Firework" singer falling for the charms of bad boy John Mayer just shortly after her failed marriage to Russell Brand.

"John has a big reputation as a serial womanizer. If people thought her ex, Russell Brand, was bad, John is notoriously a lot worse. Katy's friends are worried this is just a rebound bit of fun but will end with her getting really hurt," the source said.

John Mayer has already a long list of famous celebrity girlfriends including Jennifer Aniston, Cameron Diaz, Jennifer Love Hewitt, Kim Kardashian and Taylor Swift. Who can also forget Mayer's remarks about another famous ex-girlfriend Jessica Simpson in a Playboy interview? Mayer famously described his relationship with Jessica Simpson similar to taking drugs.

"That girl is like crack cocaine to me. Sexually it was crazy. That's all I'll say. It was like napalm, sexual napalm. Did you ever say, I want to quit my life and just f**king snort you?" Mayer said. Well, Katy Perry may have taken a bit of persuading but the ladies' man has eventually won her over.

According to reports, Perry and Mayer have been spotted together enjoying each other's company on several occasions in recent weeks putting on a display of affection at a friend's pool party in the Hollywood Hills and the two was also seen emerging from Mayer's car after a dinner date earlier this month. "There was major chemistry between them. It was like they were on a honeymoon," a source revealed.

Katy Perry's divorce from Russell Brand has been made official last month that ended their 14-month marriage. Since her split from Brand, the 27-year old Perry has been linked to male model Baptiste Giabiconi, "Florence And The Machine" guitarist Rob Ackroyd and currently with John Mayer while her now ex-husband comedian Russell Brand has finally moved on with actress Isabella Brewster.

Katy Perry for GHD

Katy Perry is number 5 at the Top Ten Social Media Celebrities list.

Katy Perry and John Mayer

John Mayer

John Mayer has decided to integrate social media into his most recent music video. The four minute compilation for "Queen of California," the latest single off Mayer's most recent critically acclaimed album "Born and Raised," uses the popular gaming app Draw Something.

Katy Perry for GHD

Singer Katy Perry poses at the 2012 MusiCares Person of the Year tribute honoring Paul McCartney in Los Angeles February 10, 2012.

Photo of singer John Mayer from a Facebook fan page.

Photo from Facebook.

"Part of Me" singer Katy Perry photo from a Facebook fan page.