AceShowbiz - A producer who helped launch Lady GaGa's career is suing the pop star for $35 million over allegations she dumped him as soon as she hit the big time. 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, who has also worked with Destiny's Child and Will Smith, 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 the star in New York on Wednesday, March 17.

The producer hit the headlines recently when he took aim at his former collaborator Beyonce Knowles, who ironically appears alongside Lady GaGa on new single "Telephone", accusing the star of taking all the credit for using a Stevie Nicks' riff in Destiny's Child's hit "Bootylicious".

Fusari claimed it was his idea to use the sample and he was upset when Beyonce claimed it was her initiative. In an interview with Billboard magazine, he said, "I came up with the idea to build a track using the guitar riff from Stevie Nicks' 'Edge of Seventeen'."

"I figured I'd put the guitar loop on there temporarily, and later go into the studio with a guitar and replay it, because I'd learned, after sampling Stevie Wonder's 'I Wish' for Will Smith's 'Wild Wild West', that I didn't want to lose 50 per cent of the publishing (royalties)."

"I vividly remember telling (Destiny's Child manager and Beyonce's father) Mathew Knowles, 'Mathew, you got to book me into your studio and let me replay that riff.' He didn't want to do it. So 50 per cent got cut for one note. That whole experience was bittersweet for me."