If Susan Boyle had her way, she'd sing a duet with Donny Osmond -- or Brad Pitt.

"He doesn't sing, but he's darned nice looking," the superstar said in an exclusive Canadian television interview on Friday on CTV's Canada AM.

Wishes like these, and countless others, were once merely wild dreams for Boyle. That was before the 50-year-old "diamond in the rough" from Scotland became an overnight sensation in 2009 on the reality show, "Britain's Got Talent."

Ten million viewers watched the shy, frumpish reality contestant open her mouth and belt out a pitch-perfect rendition of the "Les Misérables" show tune, "I Dreamed a Dream." Boyle has been living the dream of fame and fortune ever since.

"It's a bit phenomenal and just incomprehensible, really. You can't really take it in," Boyle told Canada AM co-host, Beverly Thomson.

Since that life-altering event, Boyle has sold 14 million albums worldwide, sung in front of a TV audience of half a billion in China and lived a lifestyle she barely knew existed.

She's made an estimated 5 million pounds with the release of her 2009 album, "I Dreamed a Dream" its lead off singles, "I Dreamed a Dream" and "Wild Horses."

That success continued with Boyle's 2010 album, "The Gift" and is expected to build with the November release of her third album, "Someone to Watch Over Me."

But this queen of the underdogs has never forgotten her start, or the way the audience was quick to judge her when Boyle first walked onto the stage of "Britain's Got Talent."

Boyle wasn't young. She wasn't "sexy" in her beige "Sunday" frock and matching shoes. Boyle even seemed a little kooky to the audience, who laughed derisively as she put her hand on her hip, made a saucy swivel, and told Simon Cowell, "My name is Susan Boyle."

They all laughed at who they thought they might hear.

"Never judge a book by its cover, that's the moral behind that," said Boyle.

"I've been through auditions before for television and had the door slammed in my face," she said.

Boyle holds no hard feelings over those earlier rejections. She also bears no grudge towards the infamously brusque Cowell.

"Nice guy," Boyle said with a wink.

"I think he's a lovely guy and I'd like to thank him personally for giving me a chance to show him what I can do," said Boyle.

If Cowell was snarky with her at first (and he was, according to her fans), Boyle took no offence.

"That's his persona. It would be very unfair of me to say anything else because Simon Cowell is who he is."

Boyle's fateful appearance on "Britain's Got Talent" also taught her to appreciate the power of reality TV.

"It's a great arena for people to show off," said Boyle.

"I think anything can happen and it's very powerful. It can change your life. It changed mine," she said.

"I went straight from the TV show and into a lifestyle I wasn't used to. You have to learn a lot – how to behave, how to conduct yourself in public. And fast…almost too fast. It hit me like a train. You have to adapt."

Despite those stresses, Boyle has never grown tired of singing "I Dreamed a Dream," the song that launched her career.

"When I first sang ‘I Dreamed a Dream,' I wanted to change my circumstances. The song is about a dream that may never come true. But that's turned on its head. That's why I don't get tired of it. I'm still living the dream to this day," said Boyle.

Her latest album, "Someone to Watch Over Me," has received favourable early reviews from critics.

The album's title also holds special meaning for Boyle -- it reminds her of her late mother.

"She's that special person who's watching over me right now," said Boyle.

"She would have wanted all this to happen."

Boyle's album is full of those big ballads and moving, mezzo-soprano notes that have become her signature.

"I have a lot of fun when I'm making an album, I really do," said Boyle.

"It's my favourite thing when I get into that world of recording because you're in this bubble. It's a private world with your own thoughts on a particular song and your interpretation of it," she said.

Boyle's career will soon branch out onto the big screen and onto the theatrical stage.

Her rags-to-riches life story will soon be made into a musical.

Boyle is also the focus of the upcoming documentary, "Susan Boyle: An Unlikely Superstar." The documentary airs on Sunday, Nov. 6 at 8 pm on TLC.

"The idea behind that is for people to get to know Susan Boyle's everyday life, what she gets up to, what she's like in her community," said Boyle.

"You have to share your life with the public. They want to get beneath that public image to know what Susan Boyle is really like."

That person, according to this unlikely superstar, is "really quiet and shy…mostly."

Boyle still has more dreams to accomplish in her life. One day she hopes to find a special person to share her life with.

Until then, she also offers these words of advice for those with big dreams of their own: "As they say in Scotland, give it a welly! Go for it."