Susan Boyle has reportedly stepped up her security measures after being stalked by an American woman.
 
Boyle has apparently received a number of letters from the ‘stalker’, but finally asked for extra protection when the fan turned up at her home in West Lothian, Scotland.
 
The American woman was stopped by bodyguards, but Boyle was apparently “shaken up” following the incident.  
 
"Britain's Got Talent" chief Simon Cowell has sent extra staff to look after the 48-year-old.

“Simon is not taking any chances,” a source said.

“This woman is constantly following Susan around the world. It is a middle-aged American woman who has become obsessed with her.

“At first, people thought it was no more than a nuisance. But after what happened to Leona everyone is taking extra precautions.

“This is an important month for Susan and everyone wants it to go smoothly,” the source said.