Amber Tamblyn says she was sexually assaulted by ex-boyfriend

Actress Amber Tamblyn attends the premiere of "Cesar Chavez" at the TCL Chinese Theater in Hollywood, California, March 20, 2014. (Reuters)

Actress Amber Tamblyn decided to speak out about a past sexual assault saying she felt compelled to share her story by Donald Trump's 2005 remarks bragging about groping and kissing women.

The "Sisterhood of the Traveling Pants" star wrote says on Instagram that her ex-boyfriend grabbed her by her hair and crotch and carried her out of a nightclub. She says the part of her body that Trump "described as something he'd like to grab a woman by, was bruised from my ex-boyfriend's violence for at least the next week."

Trump's GOP presidential campaign has been thrown into upheaval since the videotape of his remarks was made public Friday.

She says she's afraid her parents will see her post, but she "needed to tell a story."

Tamblyn was nominated for an Emmy for "Joan of Arcadia."

The Associated Press contributed to this report.