Bruce Jenner's ex-wife is writing a tell-all book

A source close to the 64-year-old songwriter, who has sons Brandon, 33, and Brody, 31, with the 'Keeping Up with the Kardashians' star,

said: "Linda has been writing it for years but has held off publishing it because of Bruce's transgender secret. Now she can finally be truthful about everything."

But the former beauty queen is allegedly planning to trash Bruce's third ex-wife Kris Jenner, whom he split from in October 2013 after 22 years of marriage, in the book.

The insider told Life&Style magazine: "Linda blames Kris for making Bruce go back into the closet in the '80s.

"This book won't be pretty for Kris."

Bruce recently admitted he had already begun transitioning from male to female when he first started dating Kris, 59, and stopped taking the hormones when their relationship became serious.

But he added: "I kind of downplayed it. I feel like in a lot of ways, when you loves somebody, you have a tendency, you don't want to hurt them. I probably was not as good at saying, 'This is really down deep in my soul and I don't know if I can go any farther like this.'

"It was tough on her. You see your husband, I get that. I understand...Kris is a good woman. I've got no complaints with her.

She's a good person."