FOX is belatedly airing an O.J. Simpson interview it had shelved years ago ... shelved under extreme pressure. Regan, a book publisher, helped Simpson write a book called, "If I Did It: Confessions of a Killer."
Regan interviewed Simpson on camera for the TV special and he initially drew from the book and talked hypothetically about how the murders might have been committed. The un-aired show was viewed as a confession of sorts, and now TMZ knows why.
The special airs on Sunday, March 11.