Supergirl actress Melissa Benoist has revealed she suffered domestic abuse at the hands of a former partner.

The 31-year-old star of the CBS series, who is also a passionate domestic violence campaigner, shared a video on Instagram on Wednesday with the caption, "Life Isn't Always What It Seems".

Benoist did not identify her abuser in the emotional clip, but revealed she is a "survivor of domestic violence".

The actress, who married her Supergirl co-star Chris Wood in September, said of her former abusive partner: "He was a magnanimous person, who didn't really give you a choice not to be drawn to him.

"He could be charming, funny, manipulative, devious. He was younger than me, his maturity obvious.

"For a period of time, I wasn't interested. I was newly single, gaining my bearing in a change in my life."

She alleged the abuse was emotional and manipulative before it got physical, with the unnamed abuser telling her how to dress and making her change outfits before leaving the house.

Benoist said it affected her work and she began turning down acting opportunities because her partner was jealous of her working with men.

"Work in general was a touchy subject," she said. "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 and friendships, because I didn't want to hurt him."

During the 14-and-a-half minute video she detailed the physical violent abuse that lasted for months.

She said: "The stark truth is I learned what it felt like to be pinned down and slapped repeatedly, punched so hard the wind was knocked out of me, dragged by my hair across pavement, headbutted, pinched until my skin broke, shoved into a wall so hard the dry wall broke, choked.

"I learned quickly not to lock myself in rooms because the door would be inevitably broken down. I learned not to value my property, I learned not to value myself."

Benoist recalled an incident where her attacker threw his phone so hard at her face that she had to be taken to hospital with a broken nose and a severe eye injury.

She said: "The impact tore my iris, nearly ruptured my eyeball, lacerated my skin and broke my nose. My left eye swelled shut, I had a fat lip." She added that her vision would "never be the same".

Benoist said the violence began five months into the relationship when her abuser chucked a smoothie at her face.

"The long and winding road of healing and reconciliation has brought me to this moment where I feel strong enough to talk about my experience openly, honestly and without shame," she wrote on her Instagram post.

"By sharing my story, hopefully I can empower others to seek help and extricate themselves from abusive relationships.

"Everyone deserves to be loved void of violence, fear and physical harm."

"I am survivor of domestic violence… which is something I never expected I'd be saying," she told her 3.8 million followers.

After sharing her story, Benoist, from Texas, prompted the hashtag #IStandWithMelissa to trend on Twitter, with hundreds of social media users offering the actress words of support.

The star is now dedicated to campaigning against domestic violence, often sharing inspirational and supportive messages from the I Am Not OK movement and Futures Without Violence Instagram page.