Katy Perry in 'sexual relationship' with agent despite 'still calling' John Mayer

Katy Perry is said to have struck up a romance with her agent- Michael Kives.

The 28-year-old singer - who has been single since splitting from John Mayer earlier this year - has started a relationship with her long-time friend Michael, 35, the Sun reported.

A source told America's Star magazine that the duo have been hooking up, the Sun reported.

The source said that the two were just friends in the beginning, but Perry leaned on Kives for emotional support after her break-up with Mayer.

"It's more of a sexual thing for her rather than a heavy-duty relationship," the insider said.

The source said that Perry is still calling Mayer because she can't let go and he still reaches out to her too because he loves to string his exes along.

The source added that Mayer wants a casual fling, but Kives, who previously dated Charmed actress Alyssa Milano, is hoping that their relationship will develop into something more serious.