Click to listen to Tom Morello, Tim McIlrath, Serj Tankian and Occupy Wall Street's 'We Are the 99 Percent'

Since last fall's protestor-led occupation of Zuccotti Park, Tom Morello has been an active and vocal supporter of the Occupy Wall Street movement. The guitarist has regularly gigged at rallies under the guise of his workingman alter-ego, the Nightwatchman, and most recently performed at a commemorative gathering in lower Manhattan to mark the one-year anniversary of the movement's formation.

However, this hasn't seemed like enough of a contribution to Morello; he tells Rolling Stone that he felt the Occupy canon – largely comprised of "earnest folk songs" – was missing a true rock anthem. "It's our gift to the movement," he says of "We Are the 99 Percent," a fists-against-the-wall riff-riot that Morello penned with his "brothers in arms," Rise Against singer Tim McIlrath and System of a Down singer Serj Tankian. The track is now available to stream exclusively on RollingStone.com; starting tomorrow, it will be available for free download on Morello and Tankian's Axis of Justice website.

"I wanted to do a huge riff-rock anthem," Morello says of the track, which was recorded at his own Veritas Studio in Los Angeles, and to which McIlrath and Tankian contributed by remote. "It would feel like the excitement of the global Occupy Wall Street movement."

Morello says the idea to record an Occupy anthem came to him several months ago; however, he only got the ball rolling after last week's "re-energizing" anniversary performance. The song, anchored by Black Sabbath-worthy riffing, is a hard-charging behemoth; it's a call to action for the oppressed. ("If you feel the wave crashing down/ Don't just sit there and drown/ Fight back!" McIlrath roars.) In addition to the three musicians, it also features field recordings of Occupy protestors in Zuccotti Park and Liberty Square.

The success of Occupy Wall Street, Morello believes, has hinged on its ability to "inject into the global dialogue the horrific economic inequality that plagues the planet" and highlight the "grotesque global poverty and the growing inequality in our country." Morello says that he sees evidence of the movement's success in the current presidential campaign. "When is the last time when a Republican candidate for president has had his feet held to the fire because he's too rich?" he says.