WikiLeaks founder Julian Assange caused a political firestorm and raised potent questions about censorship and information control with his massive releases of government data. Now he's communicating through music. Assange speaks up on Multi_Viral, a raging rap-rock song created by Rene Perez, or Residente, frontman and songwriter for the activist musical duo Calle 13, released online this week.

Perez, who has 8 million online followers, enlisted contributors from around the world for an online brainstorming/songwriting session in August at the Ecuadoran embassy in London, where Assange lives.

"It seemed like a good idea to know what people feel about what's happening around the world now, this global connection you can feel and see," Perez said from New York Tuesday. "We've started to use Twitter as a different kind of tool, not just to put up photos of our concerts or gossip."

He was inspired by grassroots activist groups such as Spain's 15-M and Mexico's 132, which get shoutouts in Multi_Viral. "In every country people are getting active socially and announcing it on the Internet or social networks. That inspired me to write the song with people."

Perez first visited Assange in June. "He liked the idea and wanted to collaborate right away -- as soon as he met us he started asking questions about what we wanted to do and the song's concept and what the music would be," Perez says. "He's a serious guy but also someone who laughs a lot -- we got on super well."

Their tweets announcing the Aug. 13 composition session opened with "Greetings to the FBI!," and the session quickly trended on Twitter, bringing in thousands of questions and statements in Spanish and English.

"Some people were in shock that I was with [Assange]," says Perez. "Julian gave a kind of speech talking about ... how we can work together to get more information. They could send us whatever they wanted, but on the topics of media manipulation or their fears about what's happening online, like the NSA spying on people."

Perez incorporated them into Multi_Viral's lyrics, focusing on rebellion and the power of unfettered ideas. "I raise my banner and spread it -- with only one person to read it, the world begins to change," he proclaims in Spanish. "We infiltrate, we duplicate like cells."

There's a spoken verse from Assange ("Your secrecy shows us where we will strike ... a new world is forming the power of people onto the truth"), storming rock guitar from Tom Morello of Rage Against the Machine and Audioslave and Arabic segments from Palestinian singer Kamilya Jubran.

Calle 13 released M ulti_Viral on Youtube, Twitter and as a free download Wednesday, and also posted a half-hour discussion between Assange and Perez. The song -- the group's first in four years -- will be part of Calle 13's upcoming album, their first since leaving label Sony Music Latin. The multi-Latin Grammy winning duo of Residente and Visitante (Eduardo Cabra) started as a blackly humorous reggaeton-fusion act, but has become increasingly focused on political activism.

Perez hopes Multi_Viral will go viral and inspire other musicians to speak out on similar topics.

"Awareness is very important," he said. "Especially in the States that's difficult -- there's a lot of information coming from inside, but not from the outside. It's important to have this awareness in music."

Given that his collaboration with Assange happened mostly via email, Perez figures one powerful government agency is already aware of Multi_Viral.

"For sure the first people to have our song were the NSA," he says. "Maybe they liked it and that's why I'm still alive." ___