The Foo Fighters seem to be getting all the attention today with the announcement this morning with Lauren on 101WKQX that they will be playing a special Lollapalooza Aftershow at the world fampus Metro on Friday. The tickets for that show sold-out in minutes after they went on sale just an hour after the show was announced. Now comes news that the Foos will have a very big guest singer on their new album and everyone wants to know who it is, but Dave Grohl is not spilling the weenie beenies.

• EVERYTHING LOLLAPALOOZA on 101WKQX.COM: How to win tickets to the aftershows and the fest, the interviews backstage, and more

In an European radio interview last month, Grohl stated “biggest pop star in the world” features on the group’s new album. “[He or she] sings backup on one of the heaviest songs on the record…And we’re not telling anybody who it is.” Speaking with Rolling Stone this week, the former Nirvana drummer clarified the mystery guest is more than a ‘pop star’. “This person is, I think, is more than that,” he says.

“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, I looked at [producer] Greg [Kurstin] and said, ‘OK, come in tomorrow and we’ll figure something out.’ 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.I’d be amazed if anyone can really figure it out,” Grohl says.

“But it was great and this person’s been around a long time. And I think I’ve met this person maybe a few times, but I’d never spent time with this person, and we had a blast together. Really f_cking fun. 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, ‘F_ck! I shouldn’t have said anything. We decided we were gonna make it our own dirty little secret and see if anyone can figure it out.”

“Everyone thinks Adele sang on the record,” he says. “She didn’t sing on the record. I fucking love her, she’s an amazing person – I love her personally, and I of course also love her music – but I think everyone made this correlation because Greg had produced her. I’m like, ‘F_ck, I wish it was Adele. Goddamn, that’d be amazing.'”

In the same RS article, Grohl shot down that the singer was Taylor Swift or Adele.  “Ooooh, that’d be a good one,” he says. “Wasn’t T-Swift. She’s pretty rad, but… That’s the thing. Maybe everyone should just start submitting their wish list and then the next album will be ‘We Are the World.’ We could do this.”

The Foos who made their impact on Chicago with an episode of their HBO series ‘Sonic Highways’ featuring our city’s long hardworking music scene and in the same episode the band showed how they crafted a Second City anthem in ‘Something from Nothing’. The good times with Grohl and company continued with an intimate and wild Cubby Bear show followed by a massive Wrigley Field show across the street some months later. Now we look forward to Friday’s special Metro show,a  big national arena tour, a one-day festival in October in San Bernardino, California and of course, the new album ‘Concrete and Gold’ due out Sept 15th. Oh yeah, and who can forget them being very intimate with a literal tour of garage which included a Chicago stop back in 2011.