Kerry Washington is opening up like never before, thanks to her new memoir, Thicker Than Water, which includes a life-changing revelation about her father.

In Thicker Than Water, the 46-year-old actress revealed that she recently discovered that the man she knew all her life as her father, Earl Washington, is not her biological father after all.

In an exclusive interview with People, the Scandal star said, “It really turned my world upside down.” 

Washington learned the truth while preparing to appear in Henry Louis Gates Jr.’s Finding Your Roots, a PBS series that documents celebrities learning about their ancestors through DNA testing.

Before the episode’s filming, Washington’s mother, Valerie, and her father, Earl, spoke with Gates about the secret they had held onto for decades. In the spring of 2018, the parents finally decided to have the difficult conversation with Washington after Gates suggested it would be best to get everything out in the open before filming.

“When I got this information, I was like, ‘Oh. I now know my story,'” she said, adding that she “felt a sense of relief.”

“I didn’t know what my story was, but I was playing the supporting character in their story,” she continued.

Washington learned her parents utilized an anonymous sperm donor to help conceive after struggling with fertility issues. Learning about her parents’ secret caused the actress to turn inward and begin her journey of self-discovery. She admitted some of her past struggles with anxiety, self-esteem issues and an eating disorder could have stemmed from subconsciously sensing her paternity secret.

“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 said.

Washington noted her parents were “not too thrilled” about her writing the book initially but supported their daughter in the end. However, she was willing to share her truth without their approval.

“This really is a book about me,” she said. “I now get to step into being the most important person in my life.”

Ultimately, Washington said finding out the truth gave her “so much more love and compassion and understanding” toward her parents.

She added, “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.”

Washington’s memoir, Thicker Than Water, is out on Sept. 26. Check out her interview with People below: