If you thought teaming up with Norah Jones was an odd as Foo Fighters collaborations would ever get, then strap yourself into your Dorito-stained lounge, because Shawn Stockman of Boyz II Men has layered stacked choir vocals on a track from the band’s forthcoming Concrete and Gold.

Not only that, the song is apparently the heaviest song of the album. The way it came about was pretty random, too.

“The guy from Boyz II Men walking through the parking lot, and me saying, ‘Would you sing on our record?’ And he does – on the heaviest song on the entire record,” Dave Grohl told BBC 6 Music.

“It sounds like Sabbath and Pink Floyd. It’s heavy. It’s the last song on the record. He built a choir – it’s like 40 vocals stacked. It’s insane.”

Despite the more straight-forward songs we’ve heard from the album so far, Taylor Hawkins refers to this as “the weird record” during the interview.

“Every time we start a record, Dave goes, ‘We need to get weird on this record’. Hawkins explains. “Then we always kinda pull back a little and go, ‘Let’s just make a good rock ‘n’ roll record. This is the weird record.”

Concrete and Gold is out September 15.