As the drummer for Rage Against the Machine, Brad Wilk faced plenty of tough crowds -- but none of that helped take care of his nerves the first time he sat behind the kit for Black Sabbath.

Wilk discussed the surreal experience of getting the call to play for the band in a recent behind-the-scenes documentary clip (embedded above), saying that when he was asked to fill their vacancy at the drummer position -- left open after Bill Ward split over a reported contract dispute -- he "just couldn't help but feel like the 14-year-old kid that was sitting with the record player listening to the Black Sabbath records."

Fortunately for Wilk, he eventually settled down -- and settled into the groove during the sessions for the band's new album, '13.' "After about a week and a half of settling in, I realized they poop and pee just like me," he joked to the crew. "Whether it's old stories or listening to a new riff, you really want to absorb and be a sponge."

As Noisecreep points out, Wilk won't be able to absorb any more Sabbath for awhile; now that the band is back on the road, they're playing with Tommy Clufetos, who filled in for Ward during last year's reunion gigs.