The Scottish sensation will take time off from her CD to perform on America's Got Talent finale next week
Credit: Ken McKay/Rex USA

Her first dream – winning Britain’s Got Talent – didn’t come through. But nothing will keep Scottish singing phenom Susan Boyle’s second wish – to perform in America – from coming true.

Boyle, 48, is taking some time off from completing her album, due on Nov 24, to jet across the Atlantic and perform in the States next week. She will appear on the America’s Got Talent finale on Sept. 16, PEOPLE has learned.

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To prepare for the show, the songstress from the small town of Blackburn in West Lothian, Scotland, has had two fittings this week at the up-market store Suzanne Neville in Beauchamp Place, London.

“It’s going to be sensational, really wow. But it’s obviously under wraps,” a rep for the designer says. “Susan was very excited when she came into the store about her performance and about the dress. She’s going to look amazing.”

Her American appearance will build on the remarkable buzz around her. She has already shown her career’s enormous potential, as the I Dreamed A Dream album has topped the’s pre-order charts.

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Boyle is still working on her upcoming album and has recorded the Madonna song “You’ll See,” PEOPLE confirms. She is thought to have chosen the song herself.

Her collection will also likely include tunes such as the Les Miserables hit that made her such an overnight sensation on Britain’s Got Talent. She eventually finished second in the contest.

With reporting by HELEN I. HWANG