The actor stops short of naming the partner in question who allegedly abused her, but describes him as "charming, funny, manipulative, devious", and also as being younger than she is.

"I am a survivor of domestic violence or intimate partner violence, which is something I never thought I would say let alone be broadcasting into the ether," Benoist begins in the video.

She says the violence began around five months into the relationship, and goes on to describe several incidents during which the perpetrator was violent and abusive towards her.

The first time it happened, the man threw a smoothie at her face. The bottle smacked her cheek and the liquid went all over her face.

During another incident, her partner threw an iPhone at her face, breaking her nose and almost rupturing her eyeball.

"The stark truth is I learned what it felt like to be pinned down and slapped repeatedly, punched so hard I felt the wind go out of me, dragged by my hair across pavement, head-butted, pinched until my skin broke, shoved against he wall so hard the drywall broke, choked," she says.

Following each incident, Benoist says her partner would lift her up and put her in an empty bathtub, before turning on the faucet and bringing out "the typical abuser's apology". Over time, Benoist says that she too became violent and fought back.

After the phone incident, Benoist says she broke off the relationship.

"Something inside of me broke, this was too far, I couldn't flush this one down," she says. "None of this is salacious news, it was my reality, what I went through caused a tectonic shift on my outlook on life."

She began dating the man shortly after getting out of her previous relationship, during "a period of change in her life". Benoist says jealousy became a large part of the relationship, as the man would snoop on her phone and become angry when she talked to other men.

This began to affect Benoist's work.

"Work in general was a touchy subject, he didn't want me ever kissing or even having flirtatious scenes with men which was very hard for me to avoid. So I began turning down auditions, job offers, test deals, friendship because I didn't want to hurt him," she says.

Benoist closes the video by saying that she will be healing from the experiences for the rest of her life, and cites a shocking statistic from the Department of Justice that one in four women in the United States aged 18 and older will experience severe physical violence by an intimate partner in their lifetime.

"I want the statistics to change and I hope that telling my story might prevent more stories like mine from happening," she says.

Supergirl executive producers Greg Berlanti and Sarah Schechter penned a statement Wednesday evening following Benoist's video.

"Melissa Benoist is a hero, both on and off the screen," it reads. "She is an extraordinary woman and we are proud to stand with her and behind her. We applaud her bravery and strength and we join her in hoping this incredible act of honestly encourages other people to speak up and find safety and support. We love you Melissa."

Australian Associated Press