Jessica Simpson Took Diet Pills for 20 Years After Tommy Mottola Told Her to Lose Weight

In 1997, Jessica Simpson flew to New York with the hope of turning her success with local singing competitions into a full-blown music career.

As the now-38-year-old fashion mogul, wife and mother of three explains in her upcoming memoir, "Open Book," she sang "Amazing Grace" for then-chairman & CEO of Sony Music Entertainment, parent of the Columbia label, Tommy Mottola. It was her 17th birthday.

"He wanted to sign me," writes Simpson in an excerpt of the memoir, which was published in the February 2020 issue of PEOPLE. "And then he said, 'You gotta lose fifteen pounds.'"

"What?" she recalls saying. "I was five-foot-three and weighed 118." But Jessica claims Tommy explained to her, "That's what it will take to be Jessica Simpson."

After that, the aspiring pop star "immediately went on a strict diet, and started taking diet pills, which I would do for the next twenty years." And with the weight loss, the label urged her to "show more skin."

"I started to hear voices when I was alone at night, waiting for the sleeping pill to kick in: 'Do more sit-ups, fat ass,'" she recalls. "By the time we got to the release of my second album's first single, 'Irresistible,' I was down to 103 pounds. Everyone went on about how great I looked, but I couldn't enjoy it because I was so freaking hungry."

While coping with body-image issues, the pop star found herself masking the pain of childhood sexual abuse by drinking alcohol and taking pills.

Simpson's relationships with Nick Lachey, John Mayer and Tony Romo are also discussed in the book. She's currently married to retired NFL player Eric Johnson, who she says "gave up drinking the second I did."

TooFab has contacted reps for Tommy Mottola seeking comment.

"Open Book" comes out Feb. 4.