Susan Boyle

Simon Cowell says Britain's Got Talent singing sensation Susan Boyle is "going to surprise a lot of people" with her debut album.

While some, having heard Boyle perform "I Dreamed a Dream" countless times, may think they have a good idea of what her first album will be like, "We're not going to throw out some souvenir album of show tunes," Cowell told Extra.

How did the phenomenon begin? Check out Boyle's first Talent performance

Boyle, who sifted through 350 to 400 possible tunes to include on her first CD, "was blown away by some of the song choices," Cowell said. "She's going to surprise a lot of people with this record."

Cowell also commented on Boyle's immediate breakdown that followed her rapid rise to fame.

"I think it was all boiling up," he offered. "You've got to understand, this lady had lived alone with a cat for years and years and years, and she was really, literally, the most famous person on the planet."

For the first time since Britain's Got Talent wrapped its season, Boyle will appear in an interview on Wednesday's Today Show and as part of a special edition of America's Got Talent airing that evening. Watch a preview of her sit-down with Meredith Vieira here: