Who do we contact about putting this photo of Black Sabbath’s Geezer Butler with the Backstreet Boys up in the National Portrait Gallery?

Black Sabbath bassist Geezer Butler recently attended a show by famed pop group the Backstreet Boys, and the photo they took together afterwards will befuddle historians for generations to come.

Butler, who earlier this month gave his last performance with Sabbath’s founding lineup at singer Ozzy Osbourne’s retirement concert Back To The Beginning, took to Facebook last night (Sunday, July 20) to reveal that he’d just seen the lads behind Everybody (Backstreet’s Back) play at the Sphere in Las Vegas, as part of the four-piece’s ongoing residency in Sin City.

Butler posted a photo of himself with the group and wrote in the caption: “Thanks for letting me audition, but after much consideration, I decided to stick with bass guitar (kidding).

“Great show last night, though.”

Needless to say, the Blackstreet Boys team-up has taken Butler’s fans by surprise. “The crossover I never knew I needed,” one writes.

Another adds, “From ‘Back’ To The Beginning to ‘Back’street Boys is quite the jump!”

Butler played a five-song set with his fellow Sabbath founders – Osbourne, guitarist Tony Iommi and drummer Bill Ward – at Back To The Beginning on July 5. The event was a star-studded all-dayer that took place at Villa Park, the home turf of the bassist’s beloved Aston Villa football club, in Sabbath’s hometown of Birmingham.

The bill was rounded out by the likes of Metallica, Guns N’ Roses, Slayer and Gojira, all of whom played short sets consisting of their own material and one or two Sabbath or Osbourne covers. Famed actor Jason Momoa compered and Rage Against The Machine guitarist Tom Morello was the musical director.

Tickets to Back To The Beginning sold out almost instantly upon going on sale in February, and the event was live-streamed around the world. As all proceeds went to non-profit causes based in Birmingham, it is currently estimated to be the highest-grossing charity concert of all time. Morello claims that more than $190 million will be raised overall.

Snippets of Back To The Beginning will be compiled into a 100-minute concert film and released theatrically in 2026, under the title Back To The Beginning: Ozzy’s Final Bow.

Of all the founding Sabbath members, Butler’s musical future seems the least clear. Where Osbourne, Iommi and Ward have all announced their intentions to work on solo music, the bassist recently told Classic Rock that he’s happy simply “fiddling about in my home studio”.

He added: “If I ever did write some stuff that I thought good enough for anyone else to hear, then I’d release it, but I’m quite happy just fiddling about. It’s good for the old brain cells.”

The Backstreet Boys’ Vegas residency continues on Friday, July 25. Butler probably won’t join the boy band onstage, but stranger things have happened.