"Britain's Got Talent" contestant Susan Boyle gestures to onlookers in Blackburn in West Lothian, Scotland April 21, 2009.[Agencies]

LONDON- Susan Boyle, the frumpy Scottish spinster whose amazing voice has become a global YouTube sensation, stunned audiences again on Sunday as she was voted through to the final of "Britain's Got Talent."

Singing "Memory" from the musical "Cats," the 48-year-old overcame initial nerves to produce another command performance, her soaring rendition winning the telephone vote on the talent show.

"You are one special lady, I have to say, you really are," Simon Cowell, one of the panel of three judges, said after Boyle's performance brought the audience to their feet.

Wearing a shimmering purple dress, Boyle looked far more primped and preened than she did on first appearance on the show last month, when her dowdy looks and quirky manner provoked titters from the audience, who assumed she couldn't sing.

This time, her hair was coiffed, her eyebrows were plucked and she looked almost every inch a star in the making.

"What pressure?" she said when asked afterwards if she was nervous. "It was really good tonight, I really enjoyed it ... I'm very happy to be here and thank you all for your support."

Boyle left the judges openmouthed last month with her rendition of "I Dreamed a Dream" from "Les Miserables," which almost immediately became an Internet sensation, watched more than 60 million times on YouTube.

With appearances since on U.S. chat shows hosted by Oprah Winfrey and Larry King, Boyle -- who has joked that she has never been kissed -- has become a global sensation, her age and appearance conflicting with most images of modern celebrity.

APOLOGY

After her performance on Sunday, Cowell was moved to apologize to Boyle, saying she had been poorly underestimated.

"You know what, I just want to apologize because of the way we treated you before you sang the first time," he said. "You made me and everyone else look very stupid and I'm very happy for you, very proud for you."

Boyle, who sang in choirs as a youngster but always dreamed of a career in London's West End, tried to shut him up, saying she had paid no attention to the global furor.

Since her performance in April, television crews from around the world have camped outside her home in rural Scotland and newspapers have dedicated countless pages to her.

A fan site dedicated to Boyle is titled "Never judge a book by its cover."

In Sunday's semi-final, Boyle defeated seven other acts including a belly dancer and a Darth Vader impersonator to get through to the final on Saturday.

1 of 1Full SizeShe will be joined there by Diversity, a troupe of street dancers who came second on Sunday, and two other acts yet to be decided from the second semi-final.

Boyle's meteoric rise to fame has made her the bookmakers' firm favorite to win the contest. The winner will perform at the Royal Variety Show and receive a cheque for 100,000 pounds.