Foo Fighters pulled off an incredible feat on Sept. 3, delivering an event for the ages at the Taylor Hawkins Tribute Concert in London that honored their late drummer.

Now, the band – and, more specifically, its leader Dave Grohl – face an even bigger challenge: finding a way to meet or exceed London’s triumph at the second event on Sept. 27 at Los Angeles’ Forum.

The concert is set to be another star-studded affair, with a mix of new famous faces, along with returning artists from the Wembley Stadium gig.

Here’s a look at what we know about the second Taylor Hawkins Tribute concert, along with a few questions we can’t wait to get answered.

Who’s In

There’s a decidedly Stadium Tour tone to the new acts performing in L.A. With the successful summer trek having now come to a close, Def Leppard’s Joe Elliott and Phil Collen, Motley Crue’s Nikki Sixx and Joan Jett all agreed to perform at the second Taylor Hawkins Tribute Concert. Former Skid Row singer Sebastian Bach is another new addition, as are Black Sabbath’s Geezer Butler and Kiss’ Gene Simmons. There will be a stronger female presence at the L.A. show, with Alanis Morissette, Miley Cyrus, Leann Rimes, Pink and Heart‘s Nancy Wilson in the lineup. Red Hot Chili Peppers’ Chad Smith, Rage Against the Machine’s Brad Wilk and Weezer’s Patrick Wilson are among the drummers ready to jump behind the kit.

Who’s Out

The London show opened with a rousing performance by Liam Gallagher, but the Oasis singer will not appear at the Los Angeles event. Likewise, Chrissie Hynde and Martin Chambers of the Pretenders will be absent in L.A. Brian Johnson, who delivered a set of AC/DC classics at Wembley Stadium, won’t perform either. Still, perhaps the biggest hole will be felt by the absence of Justin Hawkins. The Darkness singer was a jack-of-all-trades at the first event, performing with the Coattail Riders, Wolfgang Van Halen and Johnson in a memorable – if awkward – duet. Supergrass, Kesha, Nile Rodgers and Nandi Bushell are among the other London performers who will not participate in the L.A. show.

Who’s Coming Back

In addition to Foo Fighters, there will be a handful of holdovers from the London event. Among them were Geddy Lee and Alex Lifeson, as well as Brian May and Roger Taylor (Rush and Queen were two of Hawkins’ biggest influences). The reunited James Gang will make a second performance in L.A., and since Josh Homme and John Paul Jones are once again on the bill, it’s safe to assume there will be another Them Crooked Vultures set. Stewart Copeland, Travis Barker, Chris Chaney, Chevy Metal, Josh Freese, Omar Hakim, Shane Hawkins, Greg Kurstin, Mark Ronson, Luke Spiller, Rufus Taylor, Lars Ulrich and Wolfgang Van Halen round out the list of returning artists.

5 Lingering Questions:

Where’s Krist Novoselic?
Nirvana bassist Krist Novoselic was on the announced lineup for the London show, leading many fans to assume he would join forces with Grohl and Pat Smear for a couple of grunge classics. But Novoselic was a no-show at Wembley Stadium, with no explanation as to why (the bassist deleted his social media accounts earlier this year, so he was mum). Given the international travel involved, it’s possible the bassist’s absence was as simple as a canceled flight. His name remains on the L.A. lineup.

Who will Lars Ulrich play with?
Watching the Metallica drummer gleefully rock out behind Johnson and Grohl during a set of AC/DC material was one of the highlights of the London show. This time around, the arrangement is less obvious. Could Ulrich join forces with Butler for some Sabbath classics? Would pairing with Cyrus – who covered “Nothing Else Matters” on 2021’s The Metallica Blacklist – be out of the question? We may not know until showtime.

Who’s singing with Wolfgang Van Halen?
Justin Hawkins performed with Grohl, Wolfgang Van Halen and Josh Freese to deliver a pair of Van Halen classics in London. With the Darkness singer out for the L.A. gig, who could handle vocals? The dream scenario would be David Lee Roth or Sammy Hagar stepping up to the mic; both singers have worked with the Foos in the past. Of the vocalists we already know will be there, Bach seems to be the likeliest contender. The former Skid Row singer was an avid Van Halen fan and was once briefly considered as a replacement for Hagar. Skid Row also toured with Van Halen, opening for the band during a run of shows in 1995.

Paul McCartney again?
It’s always a thrill whenever the legendary Beatle makes an appearance, and Paul McCartney‘s performance during the London tribute show was indeed special. He performed renditions of “Helter Skelter” and “Oh! Darling” with Foo Fighters, which also featured Hynde. McCartney owns a residence in the Hollywood Hills and spends quite an amount of time in L.A., so it wouldn’t be unheard of for him to show up at the Forum show. But even if McCartney does make a second appearance, don’t expect his Beatles bandmate Ringo Starr to join him. The drummer will be touring in Canada on the day of the show.

Who else might show up?
Grohl has an extensive Rolodex of legendary friends, and he’s not afraid to invite all of them to rock. Tenacious D has long been in the Foo Fighters’ orbit and performed with the band during Grohl’s 2015 birthday bash (also held at the Forum). Elton John, who appeared in a video message during the Wembley show, has a break during touring on the day and would be a headline-grabbing addition. Hawkins idolized Jane’s Addiction, who are L.A. based and in the midst of rehearsals before a fall tour. Plus, bassist Chaney will already be there. Seems like Perry Farrell and the band could easily squeeze in a couple of classic Jane’s tunes. And then there’s Ozzy Osbourne, who has come roaring back to performing recently. Hawkins regularly covered Black Sabbath with his band Chevy Metal, and bassist Butler has already been announced as part of the concert’s lineup. Could the Prince of Darkness make an appearance? When it comes to an event like this, no guess is too outlandish.