Scottish star Susan Boyle has an obsessed fan who is stalking her by phone “all day and all night”.

The man pretends to be her brother Gerry and asks to speak to Simon Cowell.

“Susan is upset and worried. Her phone has been going at all times of the day and night. The voice on the other end claims he’s Gerry, but he clearly isn’t.”

“Susan is particularly concerned that this man also targets her pals.” The insider added: “Record label staff have also had to fend off calls as he regularly tries to get through to Simon Cowell – but everyone is aware of his ruse.” a family source told the Sun newspaper.

Boyle sang for the pope last week in front of 65,000 at a special mass in Glasgow.