Life behind bars recently turned terrifying for O.J. Simpson, Breaking Celebrity News has learned, when the disgraced football icon had a dangerous run-in with an Aryan Nation skinhead!

Former prison guard Jeffrey Felix is spilling the daunting details of the encounter at Nevada's Lovelock Correctional Center in his upcoming book, Guarding the Juice.

It all went down because of Simpson's super-sized ego, Felix claimed.