A shocking new expose lambasting KATE GOSSELIN was written by longtime pal of JON GOSSELIN’s – from plugola to payola!

THOSE explosive secrets about Kate Gosselin, including how she allegedly hit her children with a wooden spoon, are to be revealed in a bombshell new book, AND the author is a journalist who’s close friends with her ex-hubby Jon.

Journo Robert Hoffman has been friends with Jon for years, which is how he learned the supposed behind-the-scenes details of Kate’s private life, RadarOnline.com reported.

Hoffman was an employee of the local newspaper near the Gosselins' home and began working for Us magazine covering the reality show couple in 2009 when he became good friends with Jon, the blog Small Town Gosselins reports.

 “Robert Hoffman and Jon Gosselin eventually became friends, or, in my opinion, Robert ingratiated himself to Jon.

“Jon gradually included Robert in his social activities, inviting him inside the fence, including him in dinners and on trips such as the one to Las Vegas for the Wet Republic pool party,” the blog reports.

Hoffman's book contains alleged incident of repeated spanking of the Gosselin octos with a wooden spoon purportedly delineated by Kate herself in secret journals.