Next week's premiere of the latest Star Wars movie, Attack of the Clones, could be undermined by a bootleg version of the film being swapped over the web.
Experts say that up to one million people could have seen a version of the latest George Lucas blockbuster ahead of its US release on Thursday.
The bootleg was probably made using a digital camera at a private pre-launch screening and then uploaded onto the internet, experts said.
"Here you have what everyone expected to be one of the biggest films of the year, but it will already have been seen by a million people," independent media technology consultant Bruce Forest told Reuters.
Forest detected the bootleg on peer-to-peer file-sharing site, the Internet Relay Chat network, which is popular with the hacking community.
It is the latest high-profile piracy incident to hit Hollywood after Spiderman was recently beaten to the screen by an internet viewing.
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