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An ex-boyfriend and former producer of Lady Gaga has filed a lawsuit against her, claiming the Grammy winner denied him royalty payments after their romance soured, The Associated Press reports.

In the $30.5 million suit filed Wednesday at a Manhattan state court, Rob Fusari says he was instrumental in transforming Stefani Germanotta into Lady Gaga, who dropped him when her career took off, he says. "All business is personal," the lawsuit said.

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Fusari says in the suit that he took Gaga under his wing in 2006 and spent months revamping the piano player into the pop-dance phenomenon she is today, coining her stage name from Queen's "Radio Ga Ga." He has a co-producing credit on her first album, 2008's The Fame

, and songwriting credits for "Paparazzi," "Beautiful, Dirty, Rich" and "Brown Eyes." The two were romantically involved when they launched Team Love Child LLC in May 2006, a joint venture to promote Gaga's career that promised Fusari 20 percent of the share, the suit said.

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When the couple broke up, their business relationship terminated as well, and Fusari says he's been denied a 20 percent share of song royalties and 15 percent of merchandising revenue. The producer, whose credits also include Will Smith's "Wild Wild West" and Destiny's Child's "Bootylicious," says he was paid $611,000, but claims he is owed more.A rep for Gaga declined to comment to on the lawsuit.