LOS ANGELES (Reuters) - Television's Simon Cowell said on Friday he was embarrassed at his initial reaction to British singing sensation Susan Boyle, but warned that just because she is a hit with fans, she is not a winner yet.

Cowell, the creator and a judge on "Britain's Got Talent," said he was fed up with stories about the hair, eyebrows and cats of the never-married 47-year-old Boyle, and he urged her to focus now on winning the television talent competition.

"She has got four weeks to prepare for the biggest night of her life, and she has got to sing better than she sang before with all those expectations on her. But it could all go horribly wrong for her because there are so many other distractions," Cowell told TV reporters in Los Angeles.

"Get yourself together sweetheart for the big one -- the semi-final. Shut the door, choose the right song and come back as who you are, not who you want to be," he said.

Boyle, a spinster who lives alone with her cat, became one of the world's hottest celebrities last week after surprising judges with her rendition of "I Dreamed a Dream" on the popular talent show. Her performance has been watched over 50 million times on YouTube.

"We were all guilty on the panel of judging her before she sang, and we got it utterly wrong. You watch it back and it is embarrassing," said Cowell, who is well-known as the acid-tongued judge on TV talent contest " American Idol ."

"Britain's Got Talent" is open to anyone regardless of age or performing skills. It has 40 versions worldwide and the fourth season of the U.S. version, "America's Got Talent," kicks off on NBC on June 23.

"I am seriously thinking now we should hold two more open auditions (of "America's Got Talent" off the back of Susan Boyle. You don't have to be a singer who is 47 and never been kissed, but just someone who says 'I think I am talented, and I don't think people are going to judge me because of the way I look'," he said.

Recording executive Cowell, who has an option to sign Boyle if she wins the British talent show, shuttles weekly between Los Angeles and London as the judge on "American Idol" and "Britain's Got Talent."

But he dismissed suggestions that his life was stressful. "It's only stress when it doesn't work," he said. "I don't feel under any stress whatsoever when something like the Susan Boyle thing emerges. It is honestly the best