Luc Carl has threatened to sue HarperCollins over a book about Lady Gaga that portrays him as a "villain" who "didn't have time for her".
The 27-year-old American pop-singer's former boyfriend is unhappy with the depiction of him in the book 'Rivington Was Ours' written by the 'Applause' singer's longtime friend, Brendan Jay Sullivan, the New York Post reported.
The heavy-metal drummer has fired off legal letters to HarperCollins and Sullivan over the book, which includes details from Gaga's early career, including how she swapped her "thick, dark, raven-haired Italian mane" for a bad blond dye job to impress her "inattentive and possessive" boyfriend Carl.