Jessica Simpsonis opening up about her past relationship with former costarJohnny Knoxville.

In the singer’s memoir,Open Book— out now — Simpson reveals she formed an intense bond with Knoxville while filming the 2005 film,Dukes of Hazzard.

Although married toNick Lacheyat the time, she admits to having an “emotional affair” with the actor, though the pair never got physical.

“I could share my deepest authentic thoughts with him, and he didn’t roll his eyes at me. He actually liked that I was smart and embraced my vulnerabilities,” Simpson, 39, writes. “He believed in me and made me feel I could do anything.”

The “I Wanna Love You Forever” singer expresses that she “felt a force drawing [us] together” and she “wondered why [she] was open to this.” “Now I was afraid I couldn’t trust myself,” she writes.

The only person in her life at that point who had made her feel that way was, Simpson admits, her father, Joe Simpson. “Certainly not my husband,” she adds of Lachey, 46.

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Jessica Simpson and Johnny Knoxville.J. Merritt/FilmMagic

Jessica Simpson

While the two were never physically intimate, it was the emotional bond between Knoxville, 48, and Simpson that, she writes, felt like “betrayal.”

She divulges, “Johnny and I had that, which seemed far more of a betrayal to my marriage than sex.”

Simpson and Lachey divorced in 2005 after seven years together and three years of marriage.

nick Lachey Jessica simpson

During a recent appearance onThe Dr. Oz Show, the star shared there was one thing she would have done differently regarding her divorce.

“I wish I would’ve signed a prenup,” she began. “The funny thing is that Nick wanted me to sign a prenup but I was so offended. I’m like, ‘But we’re going to be together for the rest of our lives. We’re saying our vows to God and in front of all of our family and friends. This is never going to end,’ and we didn’t sign a prenup.”

When Dr. Oz asked the actress and fashion designer what her relationship with her ex is like now, she simply responded: “There is not one.”

Jessica Simpson.Kevin Mazur/Getty

Jessica Simpson signs copies of her new book “Open Book” at Barnes & Noble Union Square on February 04, 2020 in New York City.

During Lachey’s Monday appearance on theTodayshow, he revealed that he has yet to read the book.

“I’ll be honest, I obviously haven’t read the book, so I don’t know what she said or what she revealed there, but I’m certainly happy for her and her life, I know she is happy for us,” the 98 Degrees band member said.

“There’s definitely a mutual respect there, so that’s, you know — obviously it was a long time ago. We’ve all moved on,” he added sitting alongside his wife Vanessa.

source: people.com