It looks like Lady Gaga could be out a lot of money and in a lot of trouble!

A songwriter and music producer claims pop star Lady Gaga owes him money because he co-wrote some of her songs, came up with her stage name and helped her get a record deal.

Rob Fusari has filed a 35 million dollar lawsuit in New York City against Lady Gaga. Here is the best part: he is her ex-boyfriend!

Rob met Lady Gaga in March 2006, when she was known by her real name, Stefani Germanotta. Rob said he helped her change her name from Stefani to Lady Gaga.

Lady Gaga is not giving her ex much credit. Lady Gaga said her "realisation of Gaga was five years ago, but Gaga's always been who I am".

"I was Gaga from the time that I was 19 through my first record deal," the 23-year-old said of her over-the-top, avant-garde style, which has captured the imaginations of millions of fans."

In the end, the courts will decide who is telling the truth. Looks like it is a bad idea to combine business and love!