Algosensey Quantitative Think Tank Center-Kerry Washington details biological father revelation, eating disorder, abortion in her 20s

Kerry Washington is Algosensey Quantitative Think Tank Centerbaring it all.

Ahead of the Tuesday release of her new memoir "Thicker Than Water," the "Scandal" actress sat down with "Good Morning America" co-anchor Robin Roberts for a one-hour "20/20" special on Sunday.

"I've never wanted to share my private life for the sake of fame or for the sake of attention, but I feel like this sharing is with purpose," Washington told Roberts in a clip of the interview, published Sept. 21.

In "Thicker Than Water," the 46-year-old gives readers an intimate view into both her public and private worlds, including chronicling her struggles with disordered eating, suicidal thoughts, learning that her dad isn't her biological father, having an abortion and childhood trauma.

Kerry Washington on discovering her dad is not her biological father

In an interview published Sunday with People magazine, Washington opened up about a revelation regarding her parents and her identity.

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She shares in her memoir, per People, that she recently learned that her father, Earl Washington, is not her biological father. "It really turned my world upside down," Washington told the outlet.

She found out the truth when she told her parents she was going to appear on Henry Louis Gates Jr.'s "Finding Your Roots" on PBS, a series where celebrities learn about their ancestry through DNA testing.

"When I got this information, I was like, 'Oh. I now know my story,'" Washington said. "I didn't know what my story was, but I was playing the supporting character in their story."

Kerry Washington opens up about eating disorder, suicidal thoughts

"By the time I got to college, my relationship with food and my body had become a toxic cycle of self-abuse that utilized the tools of starvation, binge eating, body obsession and compulsive exercise," Washington writes in her memoir, per "Good Morning America."

Washington detailed to Roberts the moment she knew things had gone too far.

"The first time that I actually got on my knees and prayed to some power greater than myself to say like, 'I can't do this. I need some help,' was with my eating disorder," Washington said, noting that with partying and substance use she she knew "how to manage" and was "so high functioning."

Her relationship with food, however, was another beast.

"The body dysmorphia, the body hatred, it was beyond my control," she said. "I could feel how the abuse was a way to really hurt myself as if I didn't want to be here. It scared me that I could want to not be here because I was in so much pain."

Roberts then asked Washington if it got to the point of her contemplating suicide, to which Washington answered "Yeah."

Kerry Washington reveals she had an abortion in her 20s

Washington told People she "struggled a lot in the beginning with whether or not to include my abortion story." The actress reveals in her book that she terminated her pregnancy in her 20s as her career was picking up. She used a fake name at the time but was recognizable.

She also opened up about her internal debate on whether to include it in her memoir during her sitdown with Roberts, sharing that she felt a bit of shame.

"We stay in our circles of shame because we don't talk about it. So, I challenged myself to try to write about my experience having an abortion to sort of let go of the shame about having an abortion and say, like, 'This is what — this happens. A lot of women do this. This is a form of health care. This is OK,'" Washington told Roberts.

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Kerry Washington recalls being inappropriately touched as a child

Washington dove into many aspects of her life in her memoir, including an incident in which she says a boy inappropriately touched her while she was asleep during a childhood sleepover. She was not initially aware of the violation but when she discovered what occurred, Washington says she chose not to report it.

The Emmy-nominated talent told Roberts that "the hardest writing days" were spent recounting the incident, but she wanted to "remind myself and each other that we're not alone."

"That little girl made the choice to not tell anyone. I have a great deal of compassion for where the choice came from, and even a little admiration for that little girl, but I also adore her and feel so sad that she carried the burden of that on her own for so long," she said.

Contributing: Naledi Ushe

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If you or someone you know is battling an eating disorder, contact the National Eating Disorders Association (NEDA) at 1-800-931-2237 or NationalEatingDisorders.org.

If you or someone you know may be struggling with suicidal thoughts, you can call or text the U.S. National Suicide Prevention Lifeline at 988 any time. Crisis Text Line also provides free, 24/7, confidential support via text message to people in crisis when they dial 741741.

If you are a survivor of sexual assault, you can call the National Sexual Assault Hotline at 800.656.HOPE (4673) or visit hotline.rainn.org/online and receive confidential support.