Heat editor Mark Frith is quitting the weekly magazine to write a tell-all book about the world of celebrities.
Mark Frith has been the editor of Heat since 2000
The Celeb Diaries will spill the beans on stars he encountered such as the Beckhams and Amy Winehouse during eight years in the job, his publisher said.
There will also be stories on Jude Law, Jonathan Ross, Take That, Will Young and Ewan McGregor.
Frith will leave the magazine in May and The Celeb Diaries will be published in the autumn.
The book will be published by Ebury Press, which also published former Daily Mirror editor, Piers Morgan's diaries.
"The celebrity culture that Heat kick-started has become so dominant that the inside track on how it came about, what deals were struck, and who said what to whom, is a brilliant media story," said Ebury's Jake Lingwood.
"The public are going to be fascinated to hear about what really goes on in the celebrity game."
Frith began his journalism career at music magazine Smash Hits in 1990, and was appointed editor in 1994, at the age of just 23.
He left to join now-defunct Sky Magazine in 1996, moving to Heat's launch team a year later.
After becoming editor in 2000, he took sales of the then-struggling magazine from 65,000 to over 500,000 copies a week by changing it from a general entertainment title to a women's celebrity weekly.