LOS ANGELES - Natalie Portman spoke of the pain of experiencing "sexual terrorism" at a young age when she addressed a big crowd who had turned up in Los Angeles for the Women's March over the weekend.

"At 13 years old, the message from our culture was clear to me," she said of her first fan letter after her first movie Leon: The Professional was released.

The writer mentioned a "rape fantasy".

She noted that "movie reviewers talked about my budding breasts in reviews. I understood very quickly, even as a 13-year-old, that if I were to express myself sexually, I would feel unsafe and that men would feel entitled to discuss and objectify my body to my great discomfort".

Portman, 36, who starred in Black Swan and Jackie, added: "I felt the need to cover my body and to inhibit my expression and my work in order to send my own message to the world that I'm someone worthy of safety and respect.

"The response to my expression, from small comments about my body to more threatening deliberate statements, served to control my behaviour through an environment of sexual terrorism."