Apple and other online music retailers have been hit with an unexpected lawsuit on behalf of one-hit wonders The Knack, claiming copyright infringement.

The Knack had a hit with 'My Sharona'. Now the band is claiming that because iTunes and others sell Run DMC's 1986 track, 'It's Tricky', the services are guilty of infringement. This is because Run DMC's track allegedly contains samples taken from The Knack's song.

What makes this lawsuit even more amusing is that The Knack are claiming never to have heard the Run DMC track until August 2005. This is because under US law copyright infringement violations have a three-year statute of limitations.

"This is a good example of how copyright law is outdated for the internet,' said Jason Schultz, staff attorney for the Electronic Frontier Foundation.

He warned that The Knack's suit could lead into a grey area of law, leaving Apple and other online music services exposed because certain elements of copyright law in the digital age remain undefined.