NEW YORK (AP):A songwriter and music producer who claims he helped launch pop star Lady Gaga says she squeezed him out of her lucrative career after he co-wrote some of her songs, came up with her stage name and helped get her record deal.

Rob Fusari filed a US$30.5 million lawsuit against the Grammy Award-winning performer, saying his protégée and former girlfriend ditched him as her career soared.

"All business is personal," said the lawsuit, filed Wednesday in a Manhattan state court.

Lady Gaga's spokesman, Dave Tomberlin, didn't immediately respond to an email sent on Thursday by The Associated Press.

Fusari had credits on such hits as Will Smith's Wild, Wild West and Destiny's Child's Bootylicious when a friend steered the piano-playing singer - then known by her real name, Stefani Germanotta - to him in March 2006, according to his lawsuit.

Though he initially dismissed her, he realised she had star potential after hearing her play in his Parsippany, New Jersey, studio, the suit said. He spent the next several months working with her every day and "radically reshaping her approach," persuading her to drop rock riffs for dance beats, it said.

sore thumb

As they co-wrote songs such as Paparazzi and Beautiful, Dirty, Rich, which would appear on her debut album, The Fame, he transformed Germanotta into Lady Gaga, a name adapted from Queen's Radio Ga Ga, the lawsuit said.

In a 2009 interview with the AP, Lady Gaga said her "realisation of Gaga was five years ago, but Gaga's always been who I am."

"I was Gaga from the time that I was 19 through my first record deal," the 23-year-old said of her over-the-top, avant-garde style, which has captured the imaginations of millions of fans. "I always dressed like that before people knew me as Lady Gaga. I was always that way ... I stuck out like a sore thumb."

joint venture

According to the lawsuit, Lady Gaga and Fusari's relationship turned romantic and then became a business partnership in May 2006 when they created a joint venture called Team Love Child LLC to promote her career. Fusari's share was 20 per cent, it said.

Fusari - whose account of his role in the multiplatinum-selling artiste's early career has been told in interviews - says he introduced Lady Gaga to a record executive who ultimately shepherded her to Universal Music Group's Interscope Records, which released The Fame in 2008. The album has sold more than three million copies in the United States; Fusari has a producing credit.

But the lawsuit says their personal and business relationship had soured by then and he has been denied a 20 per cent share of song royalties, 15 per cent of merchandising revenue and other money he's owed. He acknowledges getting cheques for about US$611,000 but says that isn't his full share.