Source: 'Cyrus mum had affair with Michaels'

Miley Cyrus's mother Tish has reportedly been carrying on a secret affair with Bret Michaels.

The Hannah Montana star's parents recently filed for divorce, citing "irreconcilable differences" as the reason behind the split.

However, a source told US Weekly that Tish was being unfaithful behind husband Billy Ray Cyrus's back, and that the revelation caused him to end the marriage.

Michaels is said to have become "close to the family" after recording track 'Nothing To Lose' with Miley earlier this year, and the rocker allegedly began seeing Tish privately soon after.

"Billy Ray was completely unaware of what was going on," the insider said. "It was a professional relationship that turned into something more."

However, a rep for Michaels has denied the reports, saying: "There has never been an affair or a fling."