We don't always talk about rumors, but this one's just too awesome not to share. The rumor that's been floating around as of late has taken various forms, but ultimately involves Metallica, Megadeth, Slayer and Anthrax going out on tour together. If true, it would mean thrash's four leading powers-that-be would share the same bill on the road -- for the first time ever. The ultimate bill ... or the ultimate rumor?

According to Slayer guitarist Kerry King, he's heard the same rumor. He tells Metal Hammer that he's hearing Metallica kitman Lars Ulrich is actually trying to organize the tour. Of course, King wouldn't say whether the band's been approached or not, but did say this: "I think it would be cool, but I knew we had this planned before all of this Megadeth stuff started happening. They're going to Australia with us, they're going to Canada again with us. I think it would be cool for the European fans to bring that over here because, s---, we didn't even consider playing with those guys since 1990."

Yes, that doesn't actually say much, other than King thinks "it would be cool" to do the tour. But here's the tricky thing about this rumor. Of course, Megadeth mainman Dave Mustaine and Metallica don't exactly have the best relationship. Mustaine was an original member of the band, whose departure under acrimonious circumstances were made all the more acrimonious last year when Metallica entered the Rock and Roll Hall of Fame and Dave didn't get an invite. Still, King thinks the tour could happen.

"I've heard people referencing Lars," King told Metal Hammer. "I don't know Lars that well and I haven't heard it from Lars, but apparently he's talking to somebody about it. Maybe us, Metallica, Megadeth ... I think he even threw in Anthrax and I said, 'In this day and age, I know we had that time together but ... how do you leave out Machine Head?' There's better options than Anthrax and that's nothing against Anthrax, but they've just been in pieces for quite some time and that doesn't make as much sense to me."

Machine Head, too? Man, that would be sweet. Let's just throw Trivium into the mix, too, why don't we? While this rumor's a hot one that's likely to be discussed ad nauseam over the course of the next few weeks, the good thing about rumors is, they almost always end up being true.