LONDON, England (AFP) – British reality TV singing sensation Susan Boyle’s debut album went on sale Monday, having already become the most pre-ordered CD in the history of online retailer Amazon.

The worldwide success of I Dreamed a Dream has astonished retailers.

“Just eight months ago, no one was aware of the talents of Susan Boyle. Now, she has generated more Amazon pre-order CD sales globally than any other artist”, said Julian Monaghan, head of music buying at Amazon.co.uk.

“That is an incredible achievement and is testament to the fact that she has captured the hearts of people all over Britain, America and the rest of the world.”

Amazon declined to give sales figures.

On the eve of the release, Boyle, 48, performed a cover of the Rolling Stones’ hit Wild Horses on British TV show X-Factor.

She then flew to New York where she will perform at the city’s Rockefeller Plaza and make media appearances.

The Scottish church worker revealed a soaring voice behind her frumpy appearance when she appeared on the TV show Britain’s Got Talent in April.

Video of her singing I Dreamed A Dream from the musical Les Miserables on the TV show became a YouTube hit, with at least 100 million viewings.

Although she came second to dance act Diversity in the competition, she won over fans worldwide.

She initially struggled with her sudden rise to fame, and checked into a clinic suffering from exhaustion following the show.

Boyle, who has undergone an extensive makeover since becoming a star, revealed last week that she was bullied at school and teachers failed to understand that she was a slow learner.

“You’re looking at someone who would get the belt every day. ‘Will you Shut up, Susan!’ – whack!” she said in interviews in British tabloid newspapers.

“I was often left behind at school because of one thing or another. I was a slow learner.”