Alice Tan Ridley wowed the judges with her rendition of 'At Last' by Etta James on the second day of season five's auditions in New York.
Piers Morgan had described the 58-year-old's performance as the "best audition of the day" in terms of raw talent.
"I've been singing since I was young and now I'm singing underground in the subway stations," she explained, before taking the stage.
"I love singing in the subway and to see the smiles on people's faces. This is what I've been pursuing all my life. Maybe this is it, from the subway to the big stage!"
Sharon Osbourne later said that it was her "honour" to send Ridley to Las Vegas. "Millions of people must have gone back and forth on that subway," she said. "How come nobody signed you?!"
"What an amazing voice," said Howie Mandel. "I love it. I love what you did and you deserve to be heard by much more than everybody on the trains. You are wonderful."
America's Got Talent continues tonight on NBC.
> 'America's Got Talent': New York auditions 2 recap