[youtube]http://www.youtube.com/watch?v=UzgivbF1y8s[/youtube]

The second night of Metallica’s 30th Anniversary shows at the Filmore in San Francisco this past Wednesday night (December 7) was filled with some great surprises, including a set with Mercyful Fate (great to see King Diamond back in good health) and another unreleased song. But one of the standout moments of the night also came from John Bush (Armored Saint/ ex-Anthrax).

Watching Bush perform “The Four Horsemen” with Metallica is a big treat for fans because Metallica had actually asked Bush to join the band during the Kill ‘Em All period when James Hetfield wasn’t confident about singing. Hetfield even admitted this when introducing Bush to the stage that night, reportedly saying he was the only other singer he considered for the role (guess Anthrax isn’t the only Big 4 band that went gaga over the singer). But in the end, Bush turned down the position and went forward with Armored Saint, and Metallica…well, you know how that went.

However, the performance has to make one ponder about what would’ve happened if John Bush ended up joining Metallica. How would that have changed things for Metallica? Well, we may never know that answer for sure, but it’s still cool to see Metallica onstage with Bush. Maybe this will lead to Metallica performing “The Four Horsemen” with Dave Mustaine at one of the remaining 30th Anniversary shows (one can only hope).

You can watch fan filmed footage of Metallica performing “The Four Horsemen” with John Bush above.