Lady GaGa is being sued for $30.5 million by a producer who claims he co-wrote her songs.

Songwriter-and-producer Rob Fusari - who is an ex-boyfriend of the star - 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'.

The lawsuit, filed on Wednesday (17.03.10), 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.

The 'Poker Face' hitmaker - real name Stefani Germanotta - last year claimed she has had her flamboyant stage persona since she was 19.

Gaga, who is now 23, said: "I was Gaga from the time that I was 19 through my first record deal. I always dressed like that before people knew me as Lady Gaga. I was always that way. I stuck out like a sore thumb."

Rob acknowledged he has so far received cheques for approximately $611,000 but insists it is not his full share.