America Ferrera has disclosed that she was sexually assaulted as a child by a "grown man" in a heartbreaking Instagram post.

The Ugly Betty actress bravely revealed the harrowing experience as she joined the #MeToo social media movement, which was launched by actress Alyssa Milano as a rallying cry for victims of sexual harassment and assault.

With scores of male and female celebrities showing solidarity with thousands of women, Ferrera dropped her own bombshell.

"First time I can remember being sexually assaulted I was 9 years old. I told no one and lived with the shame and guilt thinking all along that I, a 9-year-old child, was somehow responsible for the actions of a grown man," she wrote in an open letter to her 592k followers.

Ferrera went on to state that, like many victims, she knew the person that attacked her.

"I had to see this man on a daily basis for years to come. He would smile at me and wave, and I would hurry past him, my blood running cold, my guts carrying the burden of what only he and I knew – that he expected me to shut my mouth and smile back.

She concluded her online outpouring by urging more women to speak out against sexual assault "so the next generation of girls won't have to live with this bullsh*t."

Ferrera's The Sisterhood Of The Travelling Pants co-star Amber Tamblyn was one of the first to applaud her honesty. Retweeting her post, she wrote: "The bravest babe I know."

A post shared by America Ferrera (@americaferrera) on

Many people who shared their personal accounts of being raped, groped, verbally abused and molested said it was cathartic and noted that it was important that women united to show the magnitude of the problem.

The 33-year-old star's post follows numerous allegations of sexual assault against shamed Hollywood producer Harvey Weinstein. Rose McGowan, Cara Delevinge, Kate Beckinsale and Gwyneth Paltrow are just a few of the stars who have accused Weinstein of sexual harassment or rape. He denies the allegations.

With Hollywood currently engulfed by Weinstein sex scandal, the floodgates have been opened with victims of sexual assault to speak out against perpetrators.

Oscar-winning actress Patricia Arquette detailed what she claimed was her own uncomfortable encounter with Hollywood director Oliver Stone hours after he refused to denounce disgraced producer Harvey Weinstein until a trial was held to prove the sexual harassment charges against him. Former Playboy model, Carrie Stevens also took to Twitter to make claims of hypocrisy, alleging that Stone had sexually assaulted her groped her at a party. Stone has yet to respond to the allegations against him.

Amazon Studios President Roy Price was suspended after facing allegations of sexual harassment from a female executive producer, Isa Hackett. And Batman star Ben Affleck publically apologised for groping former One Tree Hill actor Hilarie Burton during an appearance on MTV's Total Request Live in 2003 after his own checkered past resurfaced.