"I was a different person." Reese Witherspoon opens up on leaving an abusive relationship.

The decision to leave an abusive partner is “fraught with self-doubt”, actress and producer Reese Witherspoon tells Oprah Winfrey.

The self-doubt is made worse, the 41-year-old mother-of-three continues, “if someone damages your self-esteem”.

“There’s a range of abuse, there’s verbal and psychological abuse, as well as physical, that can be completely detrimental to your self-worth, your self-esteem and your progress in life.”

She is speaking from experience.

When asked by Winfrey, 64, during a Super Soul Conversations video what was the most difficult decision she’d ever had to make to fulfil her “destiny”, Witherspoon replied, “For me, it was leaving an abusive relationship”.

It was a long time ago and Witherspoon didn't name her abuser but she said the experience changed her on a "cellular level".

"I was a different person. It changed me at a cellular level, the fact I stood up for myself," she said.

"I didn't have self-esteem, I'm a different person now. It's part of the reason why I can stand up now and say 'yes, I am ambitious' because someone tried to take that from me."

The Big Little Lies producer said the abuse was verbal and emotional, and that there was one instance in which she knew she had to leave.

"A line was drawn in the sand, and it got crossed, and my brain just switched. I couldn't go any further. I was really young, and it was profound."

Since then, she has realised how common abusive relationships are. "I am hard pressed to find any group of women who haven't had an experience," she said.

Both Witherspoon and Winfrey have been extremely vocal throughout the #MeToo movement, which came in the wake of actress Ashley Judd publicly accusing now-disgraced film producer Harvey Weinstein of sexual abuse.

LISTEN: The Time's Up movement, explained. Post continues below.

Speaking at Elle's Women in Hollywood Celebration in October last year, soon after the Weinstein allegations surfaced, Witherspoon spoke about a director who assaulted her when she was 16 years old.

"This has been a really hard week for women in Hollywood, for women all over the world, and a lot of situations and a lot of industries are forced to remember and relive a lot of ugly truths," she told the audience, ET Online reports.

"[I feel] true disgust at the director who assaulted me when I was 16 years old and anger at the agents and the producers who made me feel that silence was a condition of my employment. I wish that I could tell you that was an isolated incident in my career, but sadly it wasn't."

Winfrey, too, has been a leader in the movement that's seeing women stand up against abuse and exploitation in the workforce and also in their own homes.

"It's not just a story affecting the entertainment industry. It's one that transcends any culture, geography, race, religion, politics, or workplace," Winfrey said as she addressed the 2018 Golden Globe Awards in January.

"So I want tonight to express gratitude to all the women who have endured years of abuse and assault because they, like my mother, had children to feed and bills to pay and dreams to pursue. They're the women whose names we'll never know."