Howie Mandel had one of the biggest surprises of his career on America's Got Talent this week - and now the young girl behind him is going live.

Madison "Maddie" Taylor Baez surprised judges and audiences Tuesday night after being asked by the audience to sing during a commercial break.

To everyone's surprise, Baez had a powerful voice that quickly caught the attention of the four judges, including Simon Cowell, who returned to the room after hearing a cappella performance of "Amazing Grace."

Mandel was so fascinated by the 11-year-old AGT superfan from Yorba Linda, California - who revealed he started singing after his father was diagnosed with stage 4 colon cancer - and was finally filled with the gold they craved.

As the crowd chanted "Golden Buzzer," Mandel told Baez, "I'm going to do something. From the audience to live shows! Are you ready? … You're amazing!" After the emotional moment, Mandel spoke to news about what prompted him to hit his golden bell and why he thinks the moment will be remembered for years to come.

"My jaw hit the table. I was shocked, I was funny, my heart is still beating since then," he said. There was something in that voice, that clarity, that power that made us turn our heads and not just turn our heads but just say, "wow."

He continued: "Wow what I feel, wow what I hear, and wow what I do. And I'm not alone. The whole audience, everyone shouted, "Golden Buzzer! They don't do much if they don't feel it. And I think America will feel it." Although Mandel, 66, has been a judge on the show for more than a decade, he says this Golden Buzzer moment feels more touching than before.