Jennifer O'Neill claimed that she is owed for 7,168 hours of overtime she completed during her 13-month employment with the 'You & I' singer.
O'Neill said that her duties included "ensuring the promptness of a towel following a shower and serving as a personal alarm clock to keep [GaGa] on schedule".
In legal papers obtained by TMZ, she alleged that GaGa expected her duties to extend to "stadiums, private jets, fine hotel suites, yachts, ferries, trains and tour buses", resulting in her often having no chance for breaks "or at times even sleep" as she reported to the 25-year-old from her "earliest waking hour".
A representative for GaGa has claimed that O'Neill's allegations are "completely without merit".
The legal challenge has been brought against the Mermaid Touring Company, who arranged for O'Neill to work with GaGa.
The 'Marry The Night' singer recently won a lawsuit against the owners of children's social networking site Moshi Monsters after they debuted a character called Lady Goo Goo.
GaGa released previously unheard track 'Stuck on F**kin You' as a festive treat for fans on Christmas Day.
Watch Lady GaGa in the video for 'Marry The Night' below: