As half of Chic, Nile Rodgers made it to No. 1 with Le Freak in 1978.

As a music producer, he has since worked with the likes of David Bowie, Madonna, Duran Duran, Diana Ross, Bryan Ferry, Bob Dylan, Eric Clapton, Jeff Beck, INXS and Britney Spears.

But his most recent work is the soundtrack to Halo 2, the eagerly awaited Xbox video game out on Tuesday.

And the veteran musician-producer is gung-ho about helping provide the musical score to an attempted alien takeover of Earth in 2552.

"I'm insane and obsessed with this project," he said in an interview from New York.

As producer, Rodgers was ringmaster for the distinctive Halo symphonic music world created by composers Martin O'Donnell and Michael Salvatori. And he had plenty of willing participants at his disposal given the number of musicians and rock bands who have become fans of the first-person shooter game.

The Halo 2 soundtrack, the first of two volumes from the game, will feature music by Incubus, Breaking Benjamin and Steve Vai. But their contributions are instrumental, part of the Halo sound that envelops the game like Saran Wrap.

"People who participated musically had to be a part of the Halo orchestra, if you will," said Rodgers. "It's not like other soundtracks."

Rodgers cut Incubus' offering, a 25-minute opus called The Odyssey, into four movements because it was so long. It features Flea, the Red Hot Chili Peppers' bassist on trumpet.

"Marty O'Donnell and I were sitting around saying 'We can't even tap our foot to this stuff, it's so complicated,' " said Rodgers. "But in the game, it's amazing. It's so amazing.

"And you're not tapping your foot, you're running and trying not get shot."

The bands didn't do it for the money, Rodgers said. Incubus didn't get a dime, but spent hours and hours on their contribution.

"Everybody did this as a labour of love," Rodgers said. "It's almost like a Woody Allen movie, where the actors are getting paid scale.

The soundtrack from the first game, 2001's Halo: Combat Evolved, is made up of 26 cuts totalling a little more than 65 minutes. The game's signature is a haunting melody with monk-like vocals.

"Marty sent me the soundtrack of the first album and I was stunned," Rodgers said. "I sat in my room listening to it and I said to myself there is something really wrong with this world. How can a composer of this quality, how can his work go unknown? This just doesn't make any sense to me."

In producing the soundtrack for the sequel, Rodgers said the key thing was to stay true to the sound that worked so well the first time out.

"It's primal music against a high-tech environment. . . . The last thing you want to do is reinvent that because it is what it is."

That didn't stop Rodgers from experimenting, like the time he asked O'Donnell to let guitar virtuoso Vai sit in the first violin's seat.

"Marty looked at me and said 'Are you nuts? I said 'Yeah, but let's check it out and try it.'

"Steve sits in the first violin chair, pulls out the chart and starts riffing though it. And it was just unbelievable. The whole studio was flipping out."

As for Vai, he said his son was more impressed with the fact he was doing the Halo 2 soundtrack that the fact he was due to play the Hollywood Bowl.

Rodgers plays Halo himself and says it is so popular with bands, that in some cases he has to lock the console away during recording sessions.

The veteran producer, whose label Sumthing Else Music Works distributes both Halo game soundtracks, says producing video game music seemed natural.

"The video game itself is the star, just like when I first started out the clubs were the stars. The music that was in the clubs, just sort of supported the environment if you will. Obviously the music had to be great or else the people wouldn't tolerate it.

"So that's what this is sort of all about. It may sound like a very wacky analogy, but for me it makes so much sense."

A second volume of the Halo 2 soundtrack is expected early next year, probably with DVD extras in addition to more music.