Sean Parker and Shawn Fanning, the "enfants terribles" whose Napster file-sharing technology helped dismantle the traditional music industry a decade ago, have joined forces again with a new service for friends to video-chat on the Web.

The pair launched Airtime at a star-studded event that featured live appearances by Hollywood actor Jim Carrey, talk show host Jimmy Fallon and TV star Joel McHale. There were also live video chats with rapper Snoop Dogg and actress Olivia Munn.

But the launch was not without its problems as the demo of the service ran into technical difficulties, as the stars milled around on stage.

Video chats between some of the celebrities broke down for more than ten minutes as technical staff rushed to help fix the problems at an event which started nearly an hour late.

Parker and Fanning will be hoping that the live service operates with fewer hiccups as it becomes available to Facebook's 950 million users. In order to use Airtime, consumers have to be registered Facebook users.

Parker said the start-up is not trying to build a new platform to rival the likes of Facebook.

Airtime is being positioned more as a social network, where friends can communicate or even 'perform' for each other. Parker said the service would benefit from the 'network effect' in that the more people who use it, the more useful it will become similar to telephone or a more modern network like Facebook.

Parker was also an early backer of Facebook, in a role that was made iconic in the Oscar-winning movie 'The Social Network', in which he was played by singer/actor Justin Timberlake.

He said the service will try to make the Internet more fun as friends can video chat with each other in real time and can also chat anonymously with people outside their social network.

The company said it will focus on safety as one of its most important priorities to help root out "bad actors" who might use the service inappropriately.

Several video communication services already exist on the Web including Microsoft Corp's Skype, Google's Hangout service and start-ups like Chatroulette.

"We're trying to restore serendipity to the Internet," Parker said. "There's never been an environment like this for live performance on the Internet."

After Parker and Fanning launched Napster in 1999, they said they had no idea the music file-sharing service would become so popular. Millions of fans downloaded the software allowing them to illegally share songs for free. It was followed by a spate of lawsuits from the major music companies that eventually shuttered the business.

"We knew the product was big but we dramatically underestimated the scale," Fanning said in an on-stage interview with Fallon.