Lady GaGa's former personal assistant is set to lift the lid on life with the superstar in a new tell-all book.

The Poker Face hitmaker endured a lengthy legal battle with Jennifer O'Neill after she sued the singer for allegedly failing to pay her overtime money.

The lawsuit, which was settled out of court last year (13), hit headlines when O'Neill testified that she was forced to sleep in the same bed as the singer, and was expected to be available to work every hour of the day.

Gaga hit back in a foul-mouthed deposition, branding her former assistant a "f**king hood rat" and accusing her of being bad at her job because she left the singer to carry her own luggage and unpack her own bags.

O'Neill has now landed a book deal with publishers at Atria Books and is writing a tell-all tome titled Fame Monster, a reference to Gaga's album of the same name.

Editors of New York Post gossip column Page Six report the book focuses on her time working for the singer between 2009 and 2011, and the deal is worth up to $1 million (£588,235).