Kerry Washington learned the truth about her biological father after she told her parents she wanted to appear on 'Finding Your Roots'

• In her new memoir, Kerry Washington revealed she learned her dad wasn't her biological father in her 40s.
• Her parents told her they used a sperm donor to conceive her before she went on "Finding Your Roots."

"Scandal" star Kerry Washington revealed in her upcoming memoir "Thicker Than Water" that she only learned her dad wasn't her biological father when she was 41 years old.

As reported by People, Washington told her parents she was considering an appearance on the hit PBS show "Finding Your Roots," where celebrities trace their family history via their DNA. At the time, she still believed her dad, Earl Washington, was her biological father.

Washington's parents, Earl and Valerie, told People that after Washington told them she was considering appearing on the show, they called "Finding Your Roots" host Henry Louis Gates Jr. to ask for advice. According to the Washingtons, Gates told them that it was best they tell their daughter the truth before she appeared on "Finding Your Roots."

They took his advice, and the reveal turned the actor's world upside down, Washington told People.

In her memoir, which will be released on September 26, Washington discusses how she now believes that this missing information about her DNA might have contributed to struggles she's had with anxiety and an eating disorder throughout her life.

"I think that dissonance of like, 'Somebody is not telling me something about my body' made me feel like there was something in my body I had to fix," she told People. Washington said she thinks she might have subconsciously known that her parents were keeping a secret from her.

Earl, who is a real estate agent, and Valerie, a professor, used a sperm donor in the '70s when they were having trouble conceiving a child. Despite the fact that they came clean to her about her paternity, Washington said that her parents were "not thrilled" when she told them that she was going to tell the world this story in a memoir.

But ultimately, knowing the truth about her DNA has strengthened Washington's relationship with her parents.

"I really started to have so much more love and compassion and understanding for my parents," said Washington, who has two biological children and one stepdaughter of her own. "Taking this deep dive into our family history made me put myself in their shoes and think about the things that they've had to navigate and what they've been through and what they've sacrificed. And it really made me feel closer to them."