After apologizing for the lack of diversity on the set of the iconic TV series "Friends," co-creator Marta Kauffman is now opening up about a transgender character's treatment on the show.

Kauffman shared it was a "mistake" that the show misgendered Chandler Bing's (Matthew Perry) parent, a trans woman named Helena. The series acknowledged the character with he/him pronouns, rather than she/her pronouns.

In an upcoming interview with "The Conversation" on the BBC World Service, Kauffman said:

“Pronouns were not yet something that I understood, so we didn’t refer to that character as ‘she.’ That was a mistake."

Kauffman discussed how she learned from the lack of representation on the set of "Friends," and how her newfound knowledge has impacted the culture on the set of her recent Netflix series, "Grace and Frankie." She even shared that she "fired a guy on the spot" for making transphobic remarks towards a trans camera person.

"I like very much to create an environment where we have a happy set and a happy crew. It’s very important to me that where we are is a safe place, a tolerant place, where there’s no yelling."

Last week, Kauffman donated $4 million to Brandeis University over the noticeable lack of racial diversity on "Friends." She said the critique was "difficult and frustrating," as she told the LA Times that, for years, she felt the show had been "singled out." After learning and listening, Kauffman had a change of heart.

"That was a very valid, extremely difficult criticism which still- I get emotional about," she shared. "If I knew then what I know now, there are certain things I would have changed. But I didn’t know them and I have since learned.”