82-year-old gives a performance you won't believe on America's Got Talent

82-year-old John Hetlinger gave a performance the judges weren't expecting on America's Got Talent.

An America's Got Talent hopeful left Simon Cowell and the other judges gob-smacked.

John Hetlinger, 82, a retired aerospace engineer and former Navy pilot, shocked everyone when he took to the stage to perform Bodies by American heavy metal band, Drowning Pool.

Cowell and his fellow judges, Heidi Klum, Howie Mandel and Spice Girl, Mel B, all looked horrified and bewildered when Hetlinger started singing the hard-rock song, which featured the lyrics, "let the bodies hit the floor".

The America's Got Talent audience also didn't quite know how to react to the performance, with some looking completely confused, while others jumped out of their seat to clap and head-bang to the song.

Heidi Klum and Simon Cowell were left shocked on America's Got Talent.

"I was not expecting that, at all!" Mel B said after Hetlinger belted out the track. "I actually got a little bit scared."

"Your face, like, totally changed," Klum added. "You were like ROOOAAARRR."

"Is there a mosh pit where you work?" Mandel joked.

"No, there's a lot of beer [though]," Hetlinger replied.

Cowell commented on how the judges thought he would come out and sing Fly Me to the Moon as a pun on his work with space craft.

"You are an animal, and I mean that in the utmost respect," Cowell said, "I absolutely love you, John."

Surprisingly, despite his bizarre performance, Hetlinger managed to win over the judges, making it through to the next round with three ''yes'' votes from the judging panel and Klum voting ''no''.

"It's awesome to see an 82-year-old man get out there and belt out some metal," Drowning Pool guitarist C.J. Pierce told Loudwire. "Whether it was our song or any song, it was just killer to see him do that."

Pierce said he hopes the band can get Hetlinger on stage with them soon, saying "he did such a great job on America's Got Talent".

- nzherald.co.nz