In 1993, Tom Morello stood naked on a stage in Philadelphia, gagged with duct tape, and facing a crowd clamouring to hear Rage Against the Machine play.

He and the band's three other members, singer Zack de la Rocha, drummer Brad Wilk and bass player Tim Commerford, had decided to stand in silence for 15 minutes before their Lollapalooza show in protest against censorship in music. The only sound, apart from the baying crowd, was the feedback from Morello and Commerford's instruments.

They were rebels.

Morello laughs about it now, because for him standing up there starkers is nothing compared to how exposed he feels when he's on stage alone as the Nightwatchman, his political folk solo project. It may be a little quieter than his band, but the politically-charged protest songs on last year's debut album, One Man Revolution, shows there's still a rebel within - a staunch Jack Johnson, if you like.

The Rage and former Audioslave guitarist started writing Nightwatchman songs about five years ago, playing them in coffee houses and at open mic nights around Los Angeles.

"I'd come off these big Audioslave arena tours and had developed this body of political folk music that I needed to air," he says on the phone from LA.

"I was very comfortable and confident in an arena of 20,000 people playing electric guitar, but in front of 20 people and a cappuccino machine it was a different story."

Early on he got some simple advice from friend and music producer, Rick Rubin, who produced Rage's covers album, Renegades, in 2000, and the first two Audioslave albums. Rubin told him to go out and play as many shows as he could.

"So I did, and I played everywhere, and after a while you couldn't stop me. The journey from those first few open mic nights to playing at the Pink Pop festival in Holland in front of 10,000 people, to playing for 50,000 steel workers in the streets of New York City, to the countless rallies, demonstrations and shows ... it's really taught me a new level of fearlessness in performance."

Morello plays the Big Day Out on January 18 as the Nightwatchman on the Green Stage at 6.15pm and then with Rage, who headline the event, on the main stage at 9.15pm.

And yes, he does get paid twice for playing two shows at festivals. "Although," he laughs, "they are very different amounts. Yeah, the first show and the second show, I tell you, there is a lot of difference in the number of zeros. But there will be no less intensity in the Nightwatchman show than the show later in the day."

Rage split in 2000 when singer Zack de la Rocha left the band over personal and musical conflicts saying "our decision-making process has completely failed; it is no longer meeting the aspirations of all four of us and from my perspective has undermined our artistic and political ideal".

Morello, Commerford and drummer Brad Wilk briefly tried to find a replacement for de la Rocha but eventually ended up forming Audioslave with ex-Soundgarden frontman Chris Cornell. The band released three hugely successful albums, the best being the first, in 2002, with songs such as Cochise, which was as close to the power of Soundgarden and Rage that Audioslave got, and the brooding Like A Stone.

But early last year, after the release of the band's third album Revelations in late 2006, said he was leaving the band "due to irresolvable personality conflicts as well as musical differences".

Not that Morello seems too cut up about it now. "The disintegration of Audioslave" was part of the reason Rage reunited when they played in front of 80,000 rabid fans at the Coachella Festival in California's Palm Desert in April. Ripping through a greatest hits set - opening with Testify off 1999's The Battle of Los Angeles and concluding with a fiery Killing In the Name from their 1992 first album - it was a triumphant return.

"For me, I just wanted to reassess my musical priorities and only wanted to be involved in music that had my world view and music that was about fighting the power and that's why I decided to make One Man Revolution and that's why I was open for playing Rage Against the Machine shows."

Being the great diplomat that Morello is - hey, this is the man who has worked with two of the most demanding and opinionated front men in rock, de la Rocha and Cornell - he talks his way out of answering any more Rage questions today.

Apparently TimeOut is not meant to ask Rage or Audioslave questions, but no one told us.

"Not to be rude or anything," says Morello politely, "but Rage Against the Machine is not doing press. With Rage Against the Machine we will speak for ourselves on stage. I'm only really doing Nightwatchman press and it wouldn't be fair to the other guys. We agreed we weren't doing any press for Australia and New Zealand."

It's odd interviewing Morello when you're not really meant to talk about Rage Against the Machine, the band that made him one of the world's most influential guitarists of recent times and revealed his staunch political views.

But he reckons - and Rage fans might disagree - that the Nightwatchman album is the heaviest thing he's done.

He realised how powerful and heavy an acoustic performance could be when he saw Bruce Springsteen's Ghost of Tom Joad tour in Santa Barbara in the late 90s.

"I'm a fan of heavy music, I'm a fan of rebel music, and there is something about when those two come together in the subtleties of a lyrical couplet and the haunting moments of silence before the final verse drops. It can be as absolutely devastating as any Marshall stack."

Others who influenced Morello in his decision to step out alone were British singer/songwriter Billy Bragg - another socialist musician who also plays the Big Day Out. In 2003 the pair played on the Tell Us The Truth Tour, which was inspired by the lies and deceptions of the Bush administration, with REM's Mike Mills and Steve Earle.

One Man Revolution doesn't tackle terrorism or the reign of President Bush directly. Instead, Morello focuses on the effects these issues have on ordinary people, like those steel workers he was talking about before.

"I felt compelled to do it for all the right reasons, and I felt I needed songs to play at the barricades and songs to fan the flames of discontent."

He is amazed how well the album is going down with a younger audience "because they don't know who Woody Guthrie is, or may not be familiar with Bruce Springsteen's Nebraska record or Billy Bragg's Talking To the Taxman About Poetry".

"So I think it's a great way to build a bridge between the rebel music of Rage, System of a Down, and even Public Enemy and the Clash, and the deep tradition of rebel music that comes with just playing acoustic guitar, three chords and the truth. The goal of this has always been 50 per cent Johnny Cash, 50 per cent Che Guevara."

He's just finished the second Nightwatchman album and wants to spread the Tom Morello word further.

"Having now found this new voice I'm looking forward to exploring it."

LOWDOWN

Who: Tom Morello
What: Guitarist, Rage Against the Machine; solo, The Nightwatchman; formerly of Audioslave
Albums: The Nightwatchman: One Man Revolution (2007); Rage Against the Machine: Rage Against the Machine, (1992); Evil Empire (1996); The Battle of Los Angeles (1999); Audioslave: Audioslave (2002); Out of Exile (2005); Revelations (2006)
Where & when: Big Day Out, January 18, Mt Smart Stadium. The Nightwatchman, Green Stage, 6.15pm; Rage Against the Machine, Blue Stage 9.15pm