The so-called “Big Four” of 1980s thrash metal — METALLICA, MEGADETH, SLAYER and ANTHRAX — played together for the first time in history on June 16, 2010 in front of 81,000 fans at the Sonisphere festival at Bemowo Airport in Warsaw, Poland and shared a bill again for six more shows as part of the Sonisphere series that same year. They reunited again for several dates in 2011, including the last “Big Four” concert, which was held on September 14, 2011 at Yankee Stadium in New York City. Since then, METALLICA, SLAYER and ANTHRAX have played a number of shows together, including the 2013 Soundwave festival in Australia. They also performed at the 2014 Heavy MTL festival in Montreal, Quebec, Canada.

Mustaine touched upon the possibility of further “Big Four” shows in a November 2022 interview with Greg Prato of Songfacts. He said: “I really think it’s time for the guys in METALLICA to step up and us do one last round, see if we can get SLAYER to come out of retirement and do a ‘Big Four’ passing of the torch to the new ‘Big Four’. It would remain to be seen who they are.

“I think it would be really cool symbolically if we did something at, like, the L.A. Coliseum, even if it’s one show and that’s it,” he continued. “SLAYER is from Los Angeles, so it would probably make it more convenient for them to go home at night. (Editor’s note: SLAYER‘s Tom Araya is a longtime Texas resident while Kerry King currently calls New York City his home. Paul Bostaph and Gary Holt live in Northern California.) I personally have been hoping for this for a while, and I keep asking and asking and asking. They’re just not into it. But that’s up to them.”

Back in 2018, Mustaine spoke about “Big Four” in an interview with “Trunk Nation LA Invasion: Live From The Rainbow Bar & Grill” on SiriusXM. Asked if there was a personal highlight for him from all the “Big Four” shows that MEGADETH has played so far, Mustaine said: “No. The whole thing was great. I can’t whittle it down to one thing. I do know that looking out in the audience and seeing everybody in black t-shirts before we started and then the rain started and all these rainbow-colored umbrellas opened up, it was the most beautiful thing. Because it went form this monochrome kind of really ugly place in Sofia, Bulgaria in the rain to just this plethora of color and just beauty, and everybody was dancing and pogoing and wheelchairs going across people’s heads and stuff. They didn’t let the rain bother them at all. Me, I felt like I was ice skating up there on the deck, ’cause it was really slippery.”

Earlier in 2018, Mustaine said that he would love play a “Big Four” show where all the bands “got treated fairly” instead of METALLICA performing a longer set and getting more stage space than the other groups on the bill. “It always kind of soured to me when you watch (METALLICA guitarist) Kirk Hammett say on the DVD (‘The Big Four: Live From Sofia, Bulgaria’), when they’re praying, and he says that ‘we’re the Big One,'” Mustaine told SiriusXM. “That just kind of shows you how the mentality was there — that it really wasn’t the ‘Big Four’; it was METALLICA and then the three of us.”

Mustaine added: “I would love to see it done in a way where we all got treated fairly and we all played together, same amount of time, same kind of stage situation, but I don’t think that’s gonna happen. And it’s cool, because SLAYER‘s gonna down in history, and they don’t need the ‘Big Four’ to make them any more legendary than they already are. Nor do I.”

Hammett said in 2017 that he believed that the “Big Four” idea would be revisited again. He explained: “I see those shows as kind of like a celebration — a real celebration of each other, and a real celebration of the music that we all make, and a real celebration of the audience embracing (what) we’ve done. And why not have more of that?”

Ten years ago, SLAYER frontman Tom Araya said that the only thing that was standing in the way of further “Big Four” shows was “the politics of character in one particular band,” with some fans speculating that he was talking about Mustaine and MEGADETH.

In his autobiography, “Mustaine: A Heavy Metal Memoir”, Mustaine addressed the issue of where his band fit in the “Big Four” order. According to The New York Times, he assured the reader that he was not offended by being put behind SLAYER. But he added an interior monologue: “O.K., we’ll play ahead of you guys on this trip, and God willing we’ll do it again sometime in the near future and we can flip things around.”

Mustaine was a member of METALLICA for less than two years, from 1981 to 1983, before being dismissed and replaced by Kirk Hammett. He went on to form MEGADETH and achieve worldwide success on his own.

Mustaine feuded with the members of METALLICA for more than two decades before finally patching things up over the last few years. He has jammed with his ex-bandmates on several occasions during “Big Four” shows and at METALLICA‘s 30th-anniversary concerts in 2011.