Susan Boyle was the runner-up of Britain's Got Talent's season 3 in 2009

Susan Boyle is making a big comeback on America’s Got Talent.

Competing for the first time since she was the runner-up of Britain’s Got Talent‘s season 3 in 2009, Boyle once again sang for judge Simon Cowell, who was there when she wowed fans with her audition performance of “I Dreamed A Dream.”

“Most of the audience, they were laughing, but they looked at my mouth, and that seemed to change. You don’t expect people to be that excited about you,” the Scottish star, 57, recalled. “I’m glad I stepped on that stage.”

Explaining why she decided to participate in the Champions series, Boyle said she hopes to be a “champion” for others.

Credit: Trae Patton/NBC

“A champion for those who maybe don’t have the confidence to do things, for those who don’t have a voice, the ones who people tend to ignore, I feel like I’m a champion for them,” she said. “Coming in second doesn’t mean you lost, it’s an unfulfilled promise.”

Boyle added, “[I’m] excited to show Simon how much I’ve grown since the last time he saw me. It’s my golden opportunity to have that promise fulfilled.”

Credit: Trae Patton/NBC

The two-time Grammy nominee’s song selection was also a walk down memory lane for some. For Monday’s premiere, Boyle chose to sing “Wild Horses,” the same song she performed on AGT‘s fourth season in 2009, which was her first-ever American TV appearance.

And no one was happier to see Boyle than Cowell.

“You know what Susan? I can’t think of any other contestant who has defined this show better than if I’m being honest with you,” he told her after her audition, which received a standing ovation. “You’re the one, you made a huge difference in a lot of people’s lives. I’m absolutely thrilled you’re here.”

Fellow judge Howie Mandel echoed the same sentiments, recalling her unforgettable BGT audition.

“That moment of watching you sing, watching you show up, it’s the epitome,” Mandel said. “We use that as vernacular in America’s Got Talent, I say, ‘You know what I want? I want that Susan Boyle moment. I want that jaw-dropping moment.’ I look for that in everything I do because you are what the show is.”

But it was Mel B who had the most memorable reaction.

“I just want to say what an absolute honor and pleasure it is to be sitting here and listening to you. Your angelic voice and I want to be the woman who gives you something you deserve,” the Spice Girl said, before she pushed the Golden Buzzer for Boyle.

During the inaugural all-star season, there is only one Golden Buzzer per episode. The four judges, including Heidi Klum, along with host Terry Crews, can give out five golden buzzers for each of the five episodes.

Other fan favorites who performed on the premiere were: sword swallower Alexandr Magala, dance crew Justice Crew, stand-up comedian Vicki Barbolak, mentalist duo The Clairvoyants, contortionist Sofie Dossi, dog act Sara and Hero, acrobat Uzeyer Novruzov, and singer Bianca Ryan.

Stand-up comedian Preacher Lawson, who competed on Monday’s episode, earned the fan-favorite vote to move forward in the competition. Lawson was the runner-up on season 12 of AGT.

“Since being on the show, I’ve sold out every club I’ve been to and I’m not broke anymore,” Lawson proudly said. “America’s Got Talent changed my life. And it’s helped me provide a better life for my whole family. So when they called me to be a part of this show, I had butterflies all over again. I definitely want to prove to people that I’ve gotten better and it’s a second chance to win.”

America’s Got Talent: The Champions airs Mondays at 8 p.m. ET on NBC.