Guns N’ Roses seem to be getting into the spirit of Black Sabbath’s upcoming Back to the Beginning concert. According to a Facebook post from SFP Magazine, the band reportedly sound-checked Black Sabbath’s classic track “Sabbath Bloody Sabbath” before their own performance at Dahls Arena in Trondheim, Norway.

The lineup—Axl Rose, Slash, Duff McKagan, and others—are currently on tour in Europe. No audio or video of the rehearsal has surfaced yet, but fans are speculating whether the band will perform the song live as part of their set.

Massive Rock Lineup Set for ‘Back to the Beginning’ Show

Guns N’ Roses will be part of the star-studded Back to the Beginning concert taking place this Saturday at Villa Park in Birmingham, England—Black Sabbath’s hometown. The all-day event will also feature legendary acts such as Metallica, Slayer, Pantera, Gojira, Halestorm, Alice in Chains, Lamb of God, Anthrax, and Mastodon.

The concert is being billed as a major celebration of heavy metal, bringing together some of the genre’s most iconic bands for one massive show.

Ozzy Osbourne’s Farewell and Sabbath Reunion

The Back to the Beginning concert also marks the final live appearance of Ozzy Osbourne and a long-awaited reunion of Black Sabbath’s original lineup: Osbourne, Tony Iommi, Geezer Butler, and Bill Ward. Ward hasn’t performed with the band since 2005 and did not participate in their 2013 reunion album 13 or the tour that followed.

“He’s doing great. He’s doing really great,” Sharon Osbourne told the BBC when the concert was announced earlier this year. “Ozzy didn’t have a chance to say goodbye to his friends, to his fans, and he feels there’s been no full stop. This is his full stop.”

The concert will be livestreamed starting at 3 p.m. BST on July 5. Fans who purchase the livestream will also have access to replay the event for an additional 48 hours.