Lady Gaga is firing back at a music producer who claims he launched her career and is suing her for $30.5m (€22.5m).
Her lawyer said in court papers made public the agreement at the heart of the suit was "unlawful".
Song writer and music producer Rob Fusari filed the lawsuit in Manhattan against the Grammy Award-winning performer. He said his protege and former girlfriend, real name Stefani Germanotta, ditched him as her career soared.
The lawsuit said they co-wrote songs such as Paparazzi and Beautiful, Dirty, Rich. Fusari also said he came up with her stage name and helped get her a record deal.
But Lady Gaga lawyer Charles Ortner said Fusari was acting as an unlawful agent "charging Lady Gaga an unlawful fee for purported services".
Fusari's lawyer, Robert Meloni, said that claim was "ludicrous" He said: "Rob was no more of an 'agent' for her than she is a Roman Catholic nun."