ANTHRAX bassist Frank Bello says that he believes SLAYER would come out of retirement to play more "Big Four" concerts.

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.

During a brand new interview with Graspop Metal Meeting, Bello spoke about whether ANTHRAX would be interested in playing more "Big Four" shows before SLAYER completes its farewell tour.

"That was a very special [thing]," he said. "I hope the 'Big Four' happens again. We're seeing so many people from the next generation that didn't get to see that, and they see the DVD of it, and they say, "When are you gonna do it again?' And I say, 'You have to talk to METALLICA. I would love to do it.'"

According to Bello, SLAYER's impending retirement should not necessarily prevent the legendary California thrashers from taking part in more "Big Four" shows if the opportunity were presented to them.

"I think if you ring up my friends in SLAYER [and tell them], 'We're doing the 'Big Four,'' I think they'd play some shows," he said. "I think they would work it out. I think [they would come out of retirement for it]. The 'Big Four' is special enough that we all rise to it. I would hope they would do that. I mean, I would certainly try to talk them into it."

The "Big Four" touring rock festival was immortalized on the "The Big Four: Live From Sofia, Bulgaria" DVD, containing footage of the June 22, 2010 Sonisphere cinecast from the Sofia, Bulgaria stop of the trek.

METALLICA guitarist Kirk Hammett said in a 2017 interview 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?"