Watch DROWNING POOL Perform 'Bodies' With 82-Year-Old 'America's Got Talent' Contestant At CHICAGO OPEN AIR

82-year-old John Hetlinger, who became a viral video sensation last month when he belted out the DROWNING POOL classic "Bodies" on the NBC series "America's Got Talent", joined the band on stage earlier today (Friday, July 15) to perform the song at the Chicago Open Air festival. Video footage of his appearance can be seen below.

The Navy veteran and aerospace manager told KUSA that he was surprised by the reaction to his "America's Got Talent" performance.

"I didn't know two and a half thousand in the audience would react the same way that 30 drunks in the bar do, but they did!" he said.

"Everybody seems to think it's great that an old man is screaming 'let the bodies hit the floor!'" John added.

Hetlinger, who was a Navy pilot, later a minister and then an aerospace engineer for Ball Aerospace in Boulder where he worked on a team that made repairs to the Hubble telescope, said that he was not bothered by any of the criticism of his performance.

"There are reviews in all the heavy metal magazines and all over the world, but they include statements like, 'Well, admittedly he doesn't sing very well,'" John said with a laugh.

John, who also has ROB ZOMBIE's "Dragula" in his repertoire, got hooked on karaoke after singing during talent shows on cruise ships in the '90s.

"He likes attention," John's wife, Marcy, said. "He's the youngest of five kids."

DROWNING POOL guitarist CJ Pierce said he first heard about Hetlinger's performance when family and friends starting texting him about it, explaining: "I picked up my phone and I got a handful of texts from a number of people because I guess it got out yesterday ahead of the airing… I watched it, and man, I am so entertained by it. It's awesome to just see an 82-year-old man get out there and just belt out some metal — whether it was our song or any song, it was just killer to see him do that."

Pierce adding jokingly about DROWNING POOL's history of changing singers, "You know, we've had a revolving door, but Jasen Moreno is our man right now. But if he doesn't work out, we always know we've got John on the backburner."

"Bodies" was DROWNING POOL's first big hit back in 2001, when it appeared on the band's debut album "Sinner". The band's original singer, Dave Williams, died that August of heart disease.

Despite being a huge rock radio smash, it was removed from radio playlists for a while later that year in the wake of the September 11 terrorist attacks.

DROWNING POOL's sixth studio album, "Hellelujah", came out earlier this year and features the singles "By The Blood" and "Hell To Pay".