Many fans took to Twitter to share their surprise after watching her on the show, with one user writing: "It makes me so sad watching Susan Boyle on BGT and the crowd laughing at her based on her looks when she said she wanted to be a singer".
Other competitors on the season premiere included an acrobatic sword swallower, a dance crew, a contortionist, another comedian, a stuntman that does ladder tricks, including a stunt that sent him to the hospital the last time he attempted it, a lady who performs tricks with her dog, a mind-reading couple The Clairvoyants, and Bianca Ryan, America's Got Talent's first victor ever, who made a comeback after suffering vocal cord paralysis in the intervening years.
Susan Boyle auditioned for America's Got Talent and was put straight through to the next round after judge Mel B pressed the golden buzzer for her.More news: USA targets suspected USS Cole bombing planner in Yemen - statement
"What an absolute honour and pleasure it is to be sitting here and listening to you and your angelic voice", she said.
When the television production saw Susan walk onto the stage, he couldn't help but express his joy: "Genuinely, I'm beyond thrilled that you're here tonight".
Simon Cowell told Susan she was the "defining" contestant of the Got Talent series.More news: NYC Mayor Announces Health Care Coverage For All New York City Residents
The America's Got Talent: The Champions team are absolutely living for golden buzzer act Susan Boyle.
Speaking before she sang, the Scottish singer recalled how Britain's Got Talent changed her life. "You don't expect people to be that excited about you", the star said.
"I had no idea but I'm glad I stayed on that stage..." Despite not winning it all, she credits the show with helping her "fulfil the dream I've had since I was 5", and in the process selling over 20 million records and becoming a household name. "Coming in second doesn't mean you lost, it's an unfulfilled promise".
She went on to release several more albums and received two Grammy nominations. "I Dreamed a Dream" and "Wild Horses" were the singles that spurred the album's success, according to IBT UK.More news: Cardinals cleared to interview Kliff Kingsbury