Megaupload bolstered its legal case against the recording industry for forcing YouTube to remove the company’s all-star promotional video, arguing that a copyright takedown notice was bogus since it had secured the signature of Black Eyed Peas front man will.i.am to appear in a video singing the file-sharing service’s praises.

The Hong Kong-based file-sharing service lodged the contract (.pdf) in federal court Wednesday as proof it had the right to include will.i.am singing, “When I’ve got to send files across the globe, I use Megaupload.”

The four-minute video featuring will.i.am and a host of other stars, including Kanye West, Mary J. Blige, Estelle and Diddy was removed from YouTube last week after Universal Music and the front man’s attorney sent YouTube takedown notices under the Digital Millennium Copyright Act.

Megaupload has been a thorn in the side of the recording industry which views Megaupload as a facilitator of rampant copyright infringement. Megaupload filed suit Monday, saying the takedown was a “sham” to silence brand-named stars from endorsing the service, and it wants a judge to order the video back online and fine Universal Music for the bogus notice.

Kim Dotcom, the chief innovation officer of the file sharing service that boasts some 50 million users, told (.pdf) a federal judge in a Thursday filing that “an attorney for will.i.am sent a DMCA notice and takedown to YouTube in connection with the Megaupload video.” Dotcom added that, “I had spoken directly with will.i.am about this issue, and he personally advised me that he absolutely had not authorized the submission of any takedown notice on his behalf.”

Under the DMCA, online service providers like YouTube lose legal immunity for their users’ actions if they don’t remove allegedly infringing content if asked to by rights holders. If the content is not removed, companies such as YouTube and Flickr could be held liable for damages under the Copyright Act, which carries penalties of up to $150,000 per violation.

Ken Hertz, will.i.am’s attorney of Beverly Hills, California, did not respond for comment. But on Tuesday, he told the Hollywood Reporter that he had sent a takedown notice because his client did not endorse the video.

Adding to the confusion, Universal Music’s takedown notice to YouTube over the same video was filed on behalf of New Zealand songwriter-singer Gin Wigmore, who isn’t even in the video.