"I'm not looking at this from the outside. I have a lot of experience.
"I know (Milano is) married to a CAA agent. Do the math. Who's behind Time's Up? CAA. Where do they meet? CAA? Who needs good PR? CAA. Who are part of the pimp problem? CAA."
In response, Milano released a statement: "I am and always have been completely supportive of Rose and admire her bravery and speaking out about her experiences".
"My goal throughout the past few months with both #MeToo and the TimesUp movement has been to use my platform to give others a voice so we can all work together to stamp out sexual harassment and sexual assault," Milano said, in the statement according to America's ABC News.
McGowan has accused disgraced Hollywood mogul Harvey Weinstein of rape — a claim Weinstein has denied.
Speaking to Nightline, McGowan suggested Weinstein was "was the de facto leader" of Hollywood's sex abuse culture.
"He was thanked … equally with God," McGowan said. "Every time was a blow. It was a bullet."
McGowan is one of 90 women who have accused Weinstein of either rape or other sexual misconduct, leading to him being fired from his own company and investigated by police in Los Angeles, New York and London.
She called Asia Argento and Annabella Sciorra — who also publicly revealed Weinstein's alleged crimes against them — "brave".
"Thank you for being brave," McGowan said, on Nightline.
"I know they're having nightmares. I know it's really triggering for so many of us out there. It's traumatising for all of us, you know?
"But it's so necessary because it's been there all along anyway, whether you want to look at it or not."