Simon Cowell has hit out at Britain’s Got Talent sensation Susan Boyle, saying she is now too famous for her own good.

The News Of The World reports that Cowell has said he is “horrified” by the global adoration given to Boyle since her first audition was shown – with even United Nations chief Kofi Annan asking Prime Minister Gordon Brown about her when they met last week.

And he has warned the 48-year-old, from West Lothian, that she has to stay out of the limelight if she wants to have any chance of winning the final.

Speaking at the launch of America’s Got Talent in California, he said, “Get yourself together, sweetheart, for the big one-which is the semi-finals.

“Choose the right song, focus yourself, shut your front door, maybe take a holiday and come back to the person you want to be and not as the person you think you should be.”

Cowell added that Susan was not even a stand-out talent. “She was just one of a group of very good auditions,” he said.

And Piers Morgan also had his say, describing her as “a 48-year-old woman with a little talent”.

However both he and Simon said they understood why she had had a makeover last week, and had her hair coloured brown and styled.

“She probably looked at herself on TV and said I need to spruce myself up a bit,” Piers said. “What woman wouldn’t? I don’t know any woman who wouldn’t have had a new hairdo in her position.”