Ian Halperin, a biographer and journalist, had spent 18 months studying the Toxic singer as an undercover paparazzo, getting closer to the star and her inner circle.
Halperin has penned down all his findings in a new book, which he hopes will hit the shelves by Christmas (08).
The singer, who already claims to be suffering from drug abuse, bipolar problems and suicidal tendencies, revealed to Halperin personally that she fears she will die at 27.
"She told me she feared she'd die at age 27 (her current age), just like other music stars, like Janis Joplin and Kurt Cobain," Contactmusic quoted Halperin as saying.
The biographer, had also ironically penned a book about Kurt Cobain - who lost his life at 27.
Joplin and Cobain aren't the only members of the sinister 27 Club, rock greats Jimi Hendrix, Jim Morrison and Brian Jones all perished before their 28th birthday.
Spears will be turning 28-years-old on 2 December (08).