Lady GaGa is counter-suing the music producer who claims he co-wrote her songs.

The 'Poker Face' singer has retaliated against her ex-boyfriend Robert Fusari - who is suing her for $30.5 million - and has claimed he tricked her into an "unlawful" arrangement to pay him 20 per cent of her royalties.

She has requested a Manhattan court order to declare their contract void, and return any money - which is thought to be approximately $611,000 - she has already paid him.

The 23-year-old singer also alleges their contract should be declared void because the music producer also worked as a talent agent - but without a license.

The lawsuit states: "The arrangement was structured in such a way as to mask its true purpose - to provide the defendant unlawful compensation for their services as unlicensed employment agents."

Songwriter-and-producer Fusari is adamant he came up with the singer's name and helped her develop her sound, co-writing songs such as 'Paparazzi' and 'Beautiful, Dirty, Rich', which eventually appeared on her debut album 'The Fame'.

He filed a lawsuit on Wednesday (17.03.10), which stated: "All business is personal."

It also details how Rob - who has writing credits on songs including 'Wild Wild West' by Will Smith and 'Bootylicious' by Destiny's Child - had been introduced to Gaga in 2006 and claims he persuaded her to drop rock riffs for a more dance-orientated sound.

The lawsuit further claims the pair became romantically involved when they set up a joint venture called Team Love Child LLC to promote her career in 2006, with Rob entitled to receive a 20 per cent share of royalties and 15 per cent of merchandising monies.

He also claims he introduced Gaga to the record company executive who eventually signed her to Interscope Records.