Last month Dave Grohl told BBC Radio 1 that “the biggest pop star in the world” would be featured on the Foo Fighters' new album, Concrete And Gold, in addition to all the other amazing guest collabs already announced, including one of the members of Boyz II Men. 

While we still don't know who the mystery star is, we've got some more hints out of Grohl.

Read more: Former Foo Fighters drummer compares Dave Grohl to a schoolyard bully

In an interview with Rolling Stone, Grohl took back his comment about the mystery person being a “pop star,” instead saying “This person is, I think, is more than that.” 

He tells the story of how this person came to be on the record, saying “It was sort of towards the end of the album and this person came up and said, 'Man, I'd really love to sing on your record'… So we found a backup part for this person to sing and we decided we were gonna make it our own dirty little secret and see if anyone can figure it out.”

Of course, he doubts that anyone could actually figure it out, but he does note that this person has “been around a long time.”

“I'd be amazed if anyone can really figure it out. But it was great and this person's been around a long time,” he continues. “And [he or she is] very talented–more so than I ever knew. But, of course, I fucking ran my mouth off; now I have to answer to it every time I pick up the telephone and I'm like, 'Fuck! I shouldn't have said anything.'”

Grohl also hinted that he'd talked to this person about doing the next season of his TV series Sonic Highways.

He's already shot down guesses of Adele and Taylor Swift, though.

Who do you think the mystery vocalist is? Leave your guesses in the comments down below! 

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