The accusation comes in the waks of Weinstein's rape conviction in New York on Monday.
The shamed movie mogul faces up to 29 year imprisonment. He will be held in jail until his sentencing on March 11.
Weinstein was acquitted of first-degree rape and two counts of predatory sexual assault.
Though McGowan says his conviction is a 'huge moment,' she expressed concern that he would be exonerated.
"He very much came after me," she said, "He and his giant machine of other monsters … people that he paid to do dastardly things.
"The other night I have to be honest I was sitting at home and I was thinking I should do the laundry and I thought if he gets convicted will he hire a hitman to kill me."
The actress has been a prominent Weinstein accuser, claiming he raped her when she was 23 and reaching a $149,000 settlement.
Immeadiately after the trail, McGowan took to social media to praise the women who spoke out against Weinstein in a scathing post.
She wrote: "I'm proud of the brave women who testified, they have taken out a monster on Earth."
"Thank you to the prosecutor and jury who said not one more."
"For once he won't be sitting comfortably," she wrote. "For once he will know what it's like to have power wrapped around his neck.
"Today is not a referendum on #MeToo. This is taking out the trash."
McGowan was not the only one to celebrate. Alleged Weinstein victims and #MeToo activists came out in force to praise the verdict.
Annabella Sciorra was a witness on the stand. "My testimony was painful but necessary," she wrote.
"I spoke for myself and with the strength of the 80-plus victims of Harvey Weinstein in my heart.
"While we hope for continued righteous outcomes that bring absolute justice, we can never regret breaking the silence.
"For in speaking truth to power we pave the way for a more just culture, free of the scourge of violence against women."
Accuser Katherine Kendall also expressed her relief to GMB.
"I was somewhat surprised as I had prepared myself for a not guilty. There was a lot of victim blaming," she said.
"I think this is just the tip of the iceberg … women will start to come forward much more now.
"I feel like this is a new day for everyone because we are saying if we can find Harvey Weinstein guilty then you too can come forward about your predator … your voice will be heard."
Former production assisstant Mimi Haleyi, who had accused Weinstein of forcing oral sex on her in 2006, told CBS This Morning, "It was just a huge relief. It was a huge relief that the jury got it.
"I just think that we're being educated about the reality of sexual assault and sexual assault victims," she said. "It's not always just a stranger. It's very often somebody that the person knows, and with that comes an entire other layer of processing."
