Before the five women came forward to accuse C K of sexual misconduct, in a New York Times expose, Maron said he previously addressed the rumours with C K himself, who rubbished them.
"Sadly, I knew what most people knew. There was a story out there, I guess going back several years, there were unnamed people in the story, it took place in a hotel room in Aspen.
"It was always out there, but then it would pick up momentum at different times. And I would ask him about it. I would say, 'This story about you forcing these women to watch you jerk off, what is that, is that true?'" Maron said on Monday's episode of his podcast, "WTF, Maron."
"So I believed my friend. It's just the environment that enabled the dismissiveness of it," Maron said.
More From This Section
C K confirmed the stories on Friday and apologised.
In the wake of the scandal, Indie distributor The Orchard cancelled the November 17 release of C K's film "I Love You, Daddy," while Netflix scrapped a planned comedy special, and HBO announced it would remove all programs from the comedian off its platforms.