Billie Joe Armstrong remembers when rock concerts could turn into real shitshows.

Sometimes, quite literally: When Green Day performed at Woodstock ’94, torrential rain transformed the grounds into a lawless slush pit, as fans hurled fistfuls of grass, mud and who knows what else at the band. “ ‘This is only the beginning,’ I thought, so I just started throwing it back,” recalls Armstrong, 47.

He’s telling the story to two other rock stars with plenty of tales of their own as they gather in a sun-splashed Los Angeles studio lounge in late August: Weezer’s Rivers Cuomo, 49, another Rock Class of ’94 graduate, and Fall Out Boy’s Pete Wentz, 40, who at the time was an unruly high school metalhead. “Everybody got so covered in mud you couldn’t tell between the crowd and the band,” continues Armstrong. “A security guard slammed [bassist] Mike [Dirnt] and broke his teeth out. We had to rush him to a dentist before we played Lollapalooza.”

These three band leaders and their groups have a combined seven No. 1s on the Billboard 200 and 15 No. 1s on Billboard’s Alternative Songs chart, which means they’re far removed these days from worrying about stray projectiles or emergency dental work. (Though Cuomo did have an encounter with an electric eel that left a scar during a swim break on 2012’s Weezer Cruise.) Yet instead of staying in their comfort zones, they’re eager to create a live experience that’s as legendary as anything else they have done. So they’re assembled here today to talk about what they’re calling the Hella Mega Tour: a joint trek -- produced by Live Nation and presented by Harley-Davidson -- that will kick off in Europe next June before coming to North America for a 20-date stadiums-only leg in July.

None of the bands have embarked an all-stadiums tour before, let alone in such company. At iconic baseball venues like Chicago’s Wrigley Field and Boston’s Fenway Park, they’ll provide, essentially, a three-hour nightly mega-mix of the music that has dominated KROQ Los Angeles playlists for the past generation -- but with the kind of star wattage that could well nudge rock closer to current pop music’s center. “The world is super hip-hop- and Instagram-[oriented], and I think this is counterprogramming to all of that,” says Wentz. “This is the biggest rock’n’roll thing that’s going to happen that summer.”

Masterminding the operation is Crush Music, the New York- and L.A.-based company that manages all three acts: Fall Out Boy since 2002 (the band has helped Crush grow as much as Crush helped it), Weezer since 2016 (Crush’s label arm has released the band’s last four albums with Atlantic) and Green Day since 2017 (when the group parted ways with its manager of 21 years, Pat Magnarella). “I asked Green Day what their goals were because they have already achieved almost every goal a band has,” recalls Crush co-founder Jonathan Daniel. “And Mike said, ‘Well, we want to play stadiums.’ ”

Green Day has played its share before, including on its last tour in 2017. But it had done so with less frequency since 2004’s American Idiot and 2009’s 21st Century Breakdown, zeitgeist-dominating albums that brought the band to commercial heights that its follow-ups (2012’s busy triple-album suite ¡Uno! ¡Dos! ¡Tré! and 2016’s return-to-form Revolution Radio) didn’t sustain. “It really came together when Fall Out Boy and Weezer were thrown out,” says Jenna Adler, who has booked Green Day for Creative Artists Agency since 1995. As Daniel puts it: “You want to make it exciting and relevant to you, not just a victory lap.”

Fall Out Boy, which went from tabloid-friendly stars of the 2000s’ mascara-punk explosion to one of this decade’s most reliable suppliers of jock jams, signed on immediately, eager to play alongside two of its heroes. Also onboard right away was Weezer, ’90s nerdcore fixtures that became unlikely 2010s crowd-pleasers thanks in part to last year’s winking cover of Toto’s “Africa”; recorded in response to a viral fan petition, it became the group’s biggest Billboard Hot 100 hit in 12 years. Together, the trio of bands is offering one of the true event-level team-ups in the live market. “You don’t see U2 and Coldplay touring together,” says Adler. “Nothing’s bulletproof, but this is about as bulletproof as you can get.”

The combined average turnout of each of the bands’ most recent tours is an estimated 27,000 fans per gig, based on figures reported to Billboard Boxscore -- not far off from baseball stadiums’ roughly 30,000-plus concert capacities, but not factoring in any overlap in their fan bases. New music should sweeten the deal, however. In addition to the tracks they all released on the day of the tour announcement in September, Green Day and Weezer both have new studio albums, Father of All... and Van Weezer, which will arrive on Feb. 7 and in May, respectively. Fall Out Boy has a greatest-hits project due Nov. 15, and it maintains a steady radio presence through non-album hits like the ILoveMakonnen and Lil Peep collaboration “I’ve Been Waiting.” “It’s one plus one equals five,” says Daniel. “Even if it’s one plus one equals two and a half, I think we’re still good to sell out stadiums.”

Aligning such star power presents unique challenges. “Everybody has to put their own ego in check because they’re sharing this tour with two other acts,” says Bob McLynn, Crush’s other co-founder, who handles much of the touring side and whom Armstrong describes as the Darth Vader to Daniel’s Yoda. (The lineup order is Weezer, Fall Out Boy and Green Day; The Interrupters will open.) But Crush knows how much good can come of its clients working together: Panic! at the Disco joined forces with Weezer for a co-headlining 2016 trek that diversified both of their fan bases and helped lay some groundwork for their recent touring and chart successes.

Stadiums are also, of course, worth playing nice for. The rare act that ascends beyond arenas and amphitheaters can feed off the energy of 40,000 of its own fans while skirting the mayhem of festival gigs. “In the last five years, we’ve seen growth in stadium touring -- a lot of it driven by utilizing ballparks,” says Live Nation senior vp North American touring Ryan McElrath, who cites Billy Joel, Coldplay and Dead & Company as recent successes. “These teams are great marketing partners. You have the opportunity to speak to the fan bases coming through those venues.”

Besides, the guys are keen to discover what they can accomplish together. “When I was 13, Guns N’ Roses and Metallica went on a big stadium tour, and my parents wouldn’t let me go,” recalls Wentz. “There’s a part of me that’s still trapped in that moment.” He glances up at Armstrong and Cuomo -- not exactly Axl Rose and Lars Ulrich when it comes to storied debauchery, but legends in their own right. “If there’s not a couple riots on this tour, was it really a success?”

What were the early conversations about the Hella Mega Tour like?

Billie Joe Armstrong: We talked about it about a year ago: Green Day wanted to do a stadium tour. We were thinking of a throwback to Monsters of Rock, which would have Van Halen, Metallica, Scorpions, all that. We were like, “Who’s that in our era?”

Rivers Cuomo: The first I heard of it was an email from Jonathan Daniel with the original Monsters of Rock poster, [asking], “Are you in?”

Pete Wentz: For us, it was like a genie saying, “You get to do a stadium tour with two bands that were your heroes growing up.” You wonder what the other two wishes are.

Armstrong: This is the most excited I have been in a long time. Especially with all the [new music]. It’s the biggest rock event that’s going to happen for over a year.

What makes stadium shows unique?

Wentz: It’s the biggest version of your show, for the most people.

Cuomo: I’ve been going to stadium shows recently since I know I have a bunch coming up. One thing that surprised me is how important your facial expressions are. You think you’re this tiny little speck, but there’s your face on this gigantic, 40-yard screen. I saw [“Gangnam Style” singer] PSY in Korea and, man, he would lift an eyebrow and 50,000 people would go nuts.

Wentz: You’re playing to a lot of casual fans. When we were playing amphitheaters with Wiz Khalifa in 2015, I remember people just walking by with nachos. They’re here because it’s the thing that’s happening on a Saturday night. Maybe they know one of our songs. You’ve somehow got to reach that person.

At Coachella this year, Weezer was one of the few rock bands on the lineup and one of the few veteran acts in general. How did that feel?

Cuomo: About fucking time! It’s the show everybody wants to play, and every year we’re waiting for the call. Rock music is so great live. I listen to all kinds of music, but when it comes to a big concert, nothing beats humans playing instruments and singing.

Wentz: There’s this guy who goes to my gym -- he’s basically an Instagram guy, and I don’t think he really cares about music. But he came back from Coachella and was like, “Weezer has so many hits!”

Armstrong: I keep thinking about the amount of hit singles that will be played at Hella Mega. It’s going to be the best DJ set ever, for multiple hours. And hopefully, we’ll have a side stage or something in the parking lot where young bands can come out and mess around, too.

In addition to those hits, you have upcoming projects. Rivers, you’re readying Weezer’s next album, Van Weezer.

Armstrong: You’re calling your album Van Weezer?

Cuomo: Yeah!

Armstrong: That’s so badass.

Cuomo: It’s a healthy mix of the Blue Album and guitar shreddage, ’80s metal riffs -- our fun, extroverted side. We feel comfortable really going for it because, at the same time, we’re making another album [for 2020] called Okay Human, which so far has no guitars. It’s all piano-based and orchestrated -- the strings were recorded at Abbey Road. It’s very introverted and quirky.

Billie, what can fans expect from Father of All...?

Armstrong: It’s very high energy -- 10 songs in 26 minutes. We wanted to create a dance groove with space between the drums and vocals [inspired by] the way Kendrick Lamar does things or old-school Motown music, where it’s leading with the rhythm. I realized I hate long songs, anything over two-and-a-half minutes. I’ve had a short attention span my whole life, even though I’ve written shit like fucking “Jesus of Suburbia” [a nine-minute epic from American Idiot].

Political commentary has been an important part of Green Day’s work. Did that seep in with an election year approaching?

Armstrong: Maybe indirectly. I can’t think of anything that’s less inspiring than trying to write about Donald Trump. It grosses me out. Everybody knows the way I feel about these things. I like to feel some sense of joy, living through the chaos of the era.

Does Fall Out Boy have any plans for a new studio album?

Wentz: I always have ideas I’m shooting to [vocalist-guitarist] Patrick [Stump], but we’re really far away from it. We’re also out of our contract [with Island Records].

In the streaming era, how wedded are all of you to the album format?

Wentz: We have feet in both worlds. There’s still a significant part of our fan base that will want to buy a physical album.

Armstrong: I’m really excited that this is the last album on our recording contract, so now we’ll be able to just put out singles and EPs or whatever we feel like doing. You don’t get stuck in some old-school cycle.

This tour is a full-circle moment for Green Day and Weezer, who both released their breakthrough albums in 1994. What did you think of each other at the time?

Cuomo: I was jealous. It was our manager’s son that produced Dookie, right?

Armstrong: Yeah, it was Bob [Cavallo’s] son, Rob.

Cuomo: So our manager was playing us [the “Longview” video] like, “This other band is going to destroy the world.” They’re tearing up furniture, and I’m like, “Damn, that’s so fucking cool!” Then we played with you guys in ’94 or ’95 in New York. We were at the peak of the Blue Album cycle. I remember you asking the crowd to spit. There were thousands of guys spitting these massive loogies, and you would go around picking them out of the air and swallowing [them]. I was like, “He’s just the greatest frontman ever.”

Armstrong: I’ve always admired [Cuomo’s] songwriting. I thought of him as the Brian Wilson of our generation.

When Fall Out Boy first got big, what did you think of them?

Cuomo: “Sugar, We’re Goin Down” is in the mode of mixolydian, and I always have just been allergic to that mode, so I didn’t get that song. I did think Patrick was incredible. Then I heard “Uma Thurman.” It’s incredible hook after incredible hook, and yet it’s hard to even identify what’s the chorus or what’s the verse. It’s so creative and mysterious.

Armstrong: I was stoked when they inducted us into the Rock & Roll Hall of Fame. I felt they were kindred spirits in the way they created culture around their band to make it fun for the fans.

All three of your bands come from scrappy beginnings. Does that prepare you to share the stage with other massive acts?

Armstrong: It’s all about community. I used to think about what it was like when The Beatles, The Rolling Stones and The Who all hung out together. I’ve always had a romantic vision of that.

Wentz: It’s the same as when you’re in a band with three other people -- any time you collaborate on something that’s bigger than you, there are compromises.

Cuomo: Lollapalooza started the year before Weezer formed, and we would go every year. It became this traveling scene, the quintessence of the alternative ethos at the time. The whole was much greater than the sum of the parts. I don’t have a single ounce of [Lollapalooza co-founder] Perry Farrell in me, unfortunately, but I’ve always looked up to him as the ultimate host of a rock event.

When veteran bands tour together, there’s a tendency to label them as just nostalgia acts. How do you avoid coming across that way?

Armstrong: Don’t stop writing music. There’s a little nostalgia that’s going to be there. Even writing songs for [1991’s] Kerplunk or Dookie, I was thinking, “I just want to be able to play these songs when I’m in my 40s.” And I think I got there.

Cuomo: I don’t want to make the same record over and over. Weezer’s early records were so influential on the current generation of producers. They’re like, “Let’s make another Blue Album or Pinkerton.” You have got to find somebody who wants to try something different.

Wentz: It becomes nostalgic when you stop betting on your future.

This article originally appeared in the Sept. 14 issue of Billboard.