'America's Got Talent': 14-Year-Old Musical Powerhouse Slays Classic James Brown Hit

After earning the Golden Buzzer earlier this season, Courtney Hadwin established herself as the show's frontrunner on Tuesday.

America's Got Talent saved its best for last during the first of the season's live rounds on Monday, bringing out 14-year-old singing phenom Courtney Hadwin for a show-stealing performance that absolutely floored the judges.

After earning the coveted Golden Buzzer from Howie Mandel during the audition rounds with a jaw-dropping performance of "Hard to Handle" by Otis Redding, the young songstress had already proven herself something of a vocal powerhouse.

The amazing thing about Hadwin is just how unexpected her larger-than-life stage presence is when you look at her, especially considering her self-described social anxiety.

"People at school didn't really get my music," the English high schooler shared in a pre-taped package that played before her performance. "Some would say I sang like a boy and that I was weird when I dance. I got the feeling that I should change and listen to everybody, but then I remembered that people like Janis Joplin, they didn't listen to anybody. And they got what they wanted in the end."

"People don't expect me to perform the way I do," she added. "But when I hear music, I come alive. I feel electrified. I just get into the music and I start moving."

Hadwin promised that she was going to give her performance in the live rounds everything she had, and she didn't disappoint.

Channeling every one of her iconic funk icons and folk-rock heroes, Hadwin pulled off a mind-blowing performance of James Brown's iconic 1965 hit "Papa's Got a Brand New Bag," that cemented her place as one of the most exciting and unexpected AGT hopefuls in the show's history.

As Hadwin finished her song to a thunderous standing ovation from the entire audience, judge Simon Cowell was so pleased with Mandel's decision to give her the Golden Buzzer that he even walked over and hugged him.

When it came time for feedback, Cowell admitted that he had no real advice for the young singer, telling her to do "everything exactly like what you did tonight."

Cowell also praised Mandel's taste in musical talent and suggested they should start a record label together.

"You are so amazing," a nearly speechless Mandel told Hadwin before just screaming with excitement and joy.

The love was universal from all the judges, with Mel B calling Hadwin "amazing" and Heidi Klum gushing over her originality.

"I have not been this excited about a new artist in a very, very long time," Klum marveled. "You definitely are in a category of your own."

ET's Denny Directo caught up with Hadwin after the episode, and the singer said the positive response was "really overwhelming."

"I really didnt think this was all gonna happen," she shared. "I was nervous when I went on stage and then when the music started, I was less nervous."

Speaking with ET, Cowell continued his praise for the dynamic performer. "I've done these shows a long time and... you always remember that one performance where you go, 'That's gonna make a difference,'" Cowell said. "And that was one of those moments. It was incredible."

Check out Hadwin's astounding audition round performance in the video below.

America's Got Talent airs Tuesdays and Wednesdays at 8 p.m. ET/PT on NBC.