The middle-aged church volunteer from a small town in Scotland became an instant global celebrity in 2009 with her heart-stopping rendition of the "Les Miserables" number "I Dreamed a Dream" on a TV talent show.
A week is a long time in showbiz—and in our hyper-speed online age three and a half years is an eternity—but Boyle is still going strong. She has sold millions of records, received an honorary doctorate, sung for Pope Benedict XVI and performed in Las Vegas. A stage musical about her life has played to enthusiastic crowds across Britain and is headed for Australia, and next month she releases her fourth album, "Standing Ovation."
But the 51-year-old singer who entered the TV talent contest to make her late mother proud is remarkably unchanged. She's still a bit frumpy, though she's acquired a new hairdo, more expensive clothes and a makeover. She still lives in her down-at-heel home town, has outbursts of anger and struggles to overcome her nerves before live performances.
It's a fairy tale, yes, but with dark shadows lurking in the corners.
"People can't accept that you can dream a dream, but part of the dream is also a nightmare," said Elaine C. Smith, a Scottish actress who knows Boyle and plays her in the biographical stage show "I Dreamed a Dream."
"Fairy dust comes out, but shrapnel comes out as well."
Boyle now has a car and chauffeur to take her to appointments, but she sticks close to familiar places and routines. She has bought a new house, a modern four-bedroom two-story in Blackburn that cost 300,000 pounds ($480,000), but locals say she often stays in the modest row house she grew up in.
And she still shows up occasionally to sing karaoke at The Crown pub.
"She belts them out like she used to and is not averse to a duet," said 20-year-old local Helen Cameron. "It's nice that this has not changed her. I think she's under a lot of pressure normally. Here she can be herself."
As well as having the support of her community, Boyle is well protected by her manager, Andy Stephens, and a close circle of friends and family—a factor that helps act as a "psychological vaccine" against the pressures of sudden fame, according to Cary Cooper, professor of psychology and health at Lancaster University.
"If you don't have the proper social support system to protect you, your celebrity status can cause you enormous stress," said Cooper, who has studied the relationship between celebrity and stress. "She is still rooted in her friends and people who know her. Most celebrities aren't."
Boyle's life changed in a few minutes when her first appearance on "Britain's Got Talent" was broadcast in April 2009. The soaring voice emerging from the dowdy, frizzy-haired figure; the audience titters turning to gasps; the shocked faces of Simon Cowell and the other judges—it was artfully staged television, but also a moment of genuine emotion.
"We judged her. Anybody who says they didn't is telling lies," Smith said. "She walked on and opened her mouth, and within minutes everybody watching was in tears."
The Internet clip went around the world, and keeps on going. On YouTube alone it has been viewed more than 106 million times.
Boyle's first album, "I Dreamed a Dream," topped both the U.K. and U.S. charts. So did her second, "The Gift."
Although Boyle's covers of pop classics and musical theater standards rarely make critics swoon, her three albums collectively have sold more than 14 million copies.
This month she's sung on "Dancing With the Stars" in the U.S. and performed in Las Vegas with Donny Osmond, a childhood idol.
It's a long way from Boyle's home town of Blackburn, a community of about 5,000 people 20 miles (32 kilometers) west of Edinburgh that lies in one of Britain's most deprived areas.
The youngest of nine children of a devout Roman Catholic family, Boyle had learning difficulties as a child, the result of oxygen deprivation at birth. She struggled in school and was bullied by other children.
She left school with few qualifications, never married—though she later said she'd exaggerated in telling the "Britain's Got Talent" judges she'd "never been kissed"—and spent years caring for her widowed mother, Bridget, who died in 2007.
The thing that gave her the greatest pleasure was singing, in church or during karaoke nights at the pub.
She has said she entered "Britain's Got Talent" in memory of her late mother, "to show her I could do something with my life."
All did not all go smoothly after her astonishing debut. During the final stages of the competition she got into a dustup with two reporters.
Although she was widely expected to win the 100,000 pound ($160,000) prize, she ended up coming second to dance troupe Diversity. After the series ended, she checked into the Priory, rehab clinic to the stars, to be treated for nervous exhaustion.
She still has outbursts of temper, and has said she still suffers anxiety when singing live before audiences.
"When I first went for 'Britain's Got Talent' I had such a feeling of failure and that's still part of me," Boyle said in an interview last year with the Daily Mail newspaper. "It's hard when that's been the pattern of your life. It's hard to believe those patterns have been broken."
Smith said Boyle's struggles—reflected in the bittersweet tone of the stage show—disappoint some of the singer's fans.
"They want the dream to come true and her life to be perfect," she said.
But Smith said Boyle's flaws are part of what makes her a star. After all, "you didn't love Judy Garland because she was perfect."
"This is a woman who is conquering the real fears she has," Smith said.
Ben McConville in Blackburn, Scotland, contributed to this report.
Jill Lawless can be reached at http://Twitter.com/JillLawless