LOS ANGELES: LADY GAGA's lawyer has hit back at a multi-million dollar lawsuit from her former mentor, insisting the business agreement between the pair was "unlawful".

Producer Rob Fusari signed a production deal with the singer in 2006, and claims to have come up with her stage moniker. He also maintains he was instrumental in landing her a deal with record label Interscope.

The hitmaker produced several tracks on Gaga's debut album, The Fame - including the hit Paparazzi - but Fusari reveals his working relationship with the star soured after she allegedly ditched him upon gaining global recognition.

He filed a lawsuit against her in New York on Wednesday (17Mar10), suing for up to $35 million (£23 million).

According to the legal papers, Gaga and Fusari created a joint company called Team Love Child LLC, of which Fusari had a 20 per cent share.

But now Gaga's lawyer, Charles Ortner, has responded to the lawsuit in a letter obtained by the Associated Press, claiming the pair's arrangement was "structured in such a way as to mask its true purpose - to provide to the defendants unlawful compensation for their services as unlicensed employment agents."

Ortner also claims Fusari and his company charged Gaga "an unlawful fee for their purported services."

But Fusari's legal representative, Robert S. Meloni, has hit back at the claims, branding them "ludicrous" and writing an email to the Associated Press, stating: "Fusari is a Partner in the Team Love LLC with Gaga and her father (through their company Mermaid). Rob was no more of an 'agent' for her than she is a Roman Catholic nun."