"We are appalled by you," writes McGowan on Twitter.
"Sharon Stone should go hangout with Catherine Deneuve. They can be misogynistic victim shamers together. I stand with @VioletPaley I heard about James Franco for years," McGowan tweeted on Wednesday. "Kill your darlings, gain your soul. Creeps."
She then shared a message she received from Violet Paley, who accused the actor of trying to pressure her into giving him oral sex. "From @VioletPaley 'Thank you. I f-cking cried when I read that. I wasn't his girlfriend yet. I was his mentee. And now the biggest headline when you look up James Franco is Sharon Stone is 'appalled' by Violet Paley.’ We are appalled by you, Sharon Stone. #RoseArmy"
"It's so hard fighting for women, all women, when others won't," added McGowan. "I'm passionate, not angry. I'm not mad, I'm sad. Big, big difference."
Speaking with Marc Maron's WTF podcast, Stone was asked about working with Franco on "The Disaster Artist."
"I'm appalled by this thing about him that's happening where the girlfriend -- I don't know how the girlfriend can say that she's offended that he asked for a blow job while they're dating and now, all of a sudden, he's a bad guy," Stone said.
"I worked with him, I know him ... He’s a kind friend, lovely professional," she added. "I don't feel like these trials without due process are entirely appropriate. I feel that it's appropriate that people have to take responsibility for the actions, but I do feel that some due process is in order."
Paley herself tweeted earlier in the day, writing, "hey @sharonstone, you don't know shit about what happened. I was no James' girlfriend when he offered to invite me to set to mentor me. I had never touched his penis. I was misguided into believing I was coming to observe set. You can delete 'activist' from your twitter bio."
Sarah Tither-Kaplan, an actress who previously accused Franco of exploiting his acting students, also tweeted at Stone. "Hi @sharonstone there are many more women who are terrified to come forward because of people like you making baseless, misguided, and victim-blaming statements like the one you did," she wrote. "They speak to me daily wondering when they will get justice. You used to be a hero of mine."
Franco's attorney denied the allegations made against his client and referred everyone to comments he made on "The Late Show with Stephen Colbert."
"Look, in my life I pride myself on taking responsibility for things that I have done," he said. "I have to do that to maintain my well being. The things that I heard that were on Twitter are not accurate. But I completely support people coming out and being able to have a voice because they didn't have a voice for so long. So I don't want to shut them down in any way."