Evan Rachel Wood, the star of hit HBO series WestWorld, has revealed in an open Twitter letter on Tuesday (Nov 29) that she was raped twice.

The 29-year-old, who had said in a recent interview with Rolling Stone magazine that she had been subjected to physical, psychological and sexual abuse, offered more details in the lengthy post.

Both rapes happened "many many years ago" and had been one of the many factors that led to an attempt to commit suicide.

Wood said she was first raped by a significant other while they were in a relationship.

The second occasion was by the owner of a bar. She added that she should have fought back but she was scared.

"I don't believe we live in a time where people can stay silent any longer," she wrote.

"I certainly can't. Not given the state our world is in with its blatant bigotry and sexism.

"It should be talked about because it's swept under the rug as nothing and I will not accept this as 'normal'. It's a serious problem.

"I am still standing. I am alive. I am happy. I am strong. But I am still not ok."

Wood has reportedly been open about her sexuality, having come out publicly as a bisexual in a 2011 interview.

She married actor Jamie Bell in 2012, but the couple divorced 19 months later. They have a three-year-old son.

In the science-fiction western thriller WestWorld, Wood plays Dolores Abernathy, a sentient android who works at a futuristic amusement park.