JENNIE GARTH plans to get revenge on ex-hubby Peter Facinelli by ripping him apart in a tell-all book!

A source says the “90210” beauty will bare intimate and embarrassing secrets in her upcoming memoir, “Deep Thoughts from a Hollywood Blonde.”

“Jennie is out for blood,” disclosed an insider.

“She’s telling friends that she’s going to reveal the real story of why her marriage failed, and that Peter is not going to come out looking good.”

The couple married in 2001, and split in 2012, amid rumors that “The Twilight Saga” actor had cheated on Jennie.

“Peter begged Jennie to leave out any references that made him look like a cad or painted him in a bad light,” divulged the source.

“But Jennie told him that he should have thought about that when he was running around on her.”

The pair – parents of daughters Luca, 16, Lola, 11, and Fiona, 7 – finalized their divorce in June.

As The ENQUIRER has reported, Jennie’s second post-divorce romance with media executive Michael Shimbo flamed out because she hasn’t been able to get over the messy split.

Jennie, 41, has lashed out at Peter, 40, over his public displays of affection with his girlfriend, actress Jaimie Alexander, 29. She also hit the roof when the couple moved into a home on the same street in Toluca Lake, Calif., where Peter and Jennie lived during their 11-year marriage.

“It’s obvious Jennie still has an ax to grind with Peter,” said the source, “and this book is definitely going to tear open old wounds between them.”