Foo Fighters are getting sexy for their ninth studio album, Concrete and Gold. For the self-professed “heaviest track” on the album, the Foos recruited Boyz II Men singer Shawn Stockman to sing backup vocals 40 layers deep.

A couple weeks ago, Dave Grohl teased that “the biggest pop star in the world” had guested on Concrete and Gold, singing backup on one of the album’s heaviest cuts. Names like Adele and Lady Gaga were thrown around by inquisitive fans. While it remains to be seen who that person is, we do know that Boyz II Men's Shawn Stockman is at least one of the guest singers on the disc.

Grohl spoke about the new track in more detail with BBC Radio, comparing it to a mix between Black Sabbath and Pink Floyd. “The guy from Boyz II Men walking through the parking lot and me saying ‘Ahh, dude, would you sing on our record?’ And he does … It’s heavy,” Grohl says. “It’s the last song on the record with the guy from Boyz II Men singing a choir. He built a choir, it’s like 40 vocals stacked. It’s insane.”

According to the track listing, the last song on the album is the title track, "Concrete and Gold."

Drummer Taylor Hawkins actually described how “weird” the new album is going to sound. “Every time we start a record, Dave goes, ‘Maybe we need to really get weird on this record,’ and then we always kind of pull back a little bit. I think we got weird. Josh Homme, our good mate from Queens of the Stone Age, said, ‘You guys made a weird record.’”

Foo Fighters’ Concrete and Gold will see a Sept. 15 release date.

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