Watch: MACHINE HEAD's ROBB FLYNN Joins VIO-LENCE On Stage At Poland's MYSTIC FESTIVAL

MACHINE HEAD frontman Robb Flynn joined his former band VIO-LENCE on stage on Wednesday, June 5 at the Mystic Festival in Gdansk, Poland to perform the song "World In A World". Fan-filmed video of his appearance can be seen below.

Although Flynn was part of VIO-LENCE's classic incarnation and played on the band's debut album, "Eternal Nightmare", the longtime MACHINE HEAD frontman wasn't approached about taking part in VIO-LENCE's 2018 reunion.

VIO-LENCE released three studio albums between 1988 and 1993. The group reformed soon after guitarist Phil Demmel acrimoniously left MACHINE HEAD more than five years ago.

Singer Sean Killian, who initiated VIO-LENCE's reunion several months after undergoing a successful liver transplant surgery, discussed the possibility of Flynn playing with VIO-LENCE again in a February 2022 interview with El Cuartel Del Metal. He said: "Well, at the time we got back together, that wasn't gonna happen. Robb's got a thing — MACHINE HEAD's a big band; it's a business; they're out touring; people love 'em; they do great. He and Phil, they got personality conflicts over the years. That happens when you're in such tight-knit quarters with people. I can't speak for Robb or Phil but I know that I like 'em both. I was texting Robb the other day.

"For me, I haven't experienced any of what those guys experienced together, so I can't comment on it [except to say] I like 'em both and they're both my friends," the singer continued. "I consider both of 'em my good friends.

"Would Robb play with VIO-LENCE? If it was convenient and it worked out… Obviously, he wouldn't play if Phil was playing, but if Phil was doing something else and we needed a guitar player, I don't know that Robb would say he wouldn't do it. Because we all just have a good time. And he recognizes that VIO-LENCE is a band that just goes out 'cause we love it — we like to write; we like to play live shows; we love the energy from the crowd that the music gets out of 'em.

"Would Robb play with us? I can't speak for him, but if the moment was right, I think he would wanna taste that again," Killian added.

Demmel, who isn't part of VIO-LENCE's current touring lineup, told Dean Delray's "Let There Be Talk" podcast in a 2021 interview that he hadn't spoken to Flynn since he left MACHINE HEAD and added that he had no "desire or need to talk to him ever again."

Demmel left MACHINE HEAD at the end of the band's fall 2018 North American tour. He was in MACHINE HEAD for nearly 16 years, during which time he played on five of the group's studio albums: "Through The Ashes Of Empires" (2003),"The Blackening" (2007),"Unto The Locust" (2011),"Bloodstone & Diamonds" (2014) and "Catharsis" (2018).

VIO-LENCE released a new EP, "Let The World Burn", in March 2022 via Metal Blade Records.

Filling out the band's ranks on "Let The World Burn" alongside Killian and Demmel were original drummer Perry Strickland, former OVERKILL guitarist Bobby Gustafson and former FEAR FACTORY bassist Christian Olde Wolbers.

Killian and Olde Wolbers are the only VIO-LENCE members from the "Let The World Burn" recording lineup who are still touring with the band.

"Let The World Burn" was recorded with Juan Urteaga at Trident Studios (TESTAMENT, MACHINE HEAD, EXODUS),with mixing handled by Tue Madsen (THE HAUNTED, MESHUGGAH) and Grammy Award-winning engineer Ted Jensen (ALICE IN CHAINS, DEFTONES, PANTERA).