"Friends" co-creator Marta Kauffman has apologized for not including any Black actors in the highly-popular '90s sitcom.

Kauffman, 65, claimed she had a hard time understanding the "difficult and frustrating" criticism and chalked it up to "Friends" being singled out. Now, she's apologizing and pledging $4 million to her alma mater, Brandeis University.

"I’ve learned a lot in the last 20 years," Kauffman said in a Zoom interview with the Los Angeles Times.

"Admitting and accepting guilt is not easy. It’s painful looking at yourself in the mirror. I’m embarrassed that I didn’t know better 25 years ago."

Cast and crew of "Friends" on set

Executive Producer David Crane, left, and David Schwimmer directing an episode of "Friends" with executive producer Marta Kauffman. (NBCU Photo Bank/NBCUniversal)

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"Friends" was set in New York City and followed a group of six friends living in the city.

Kauffman's pledge will go to support the university's African and African American Studies program.

"It took me a long time to begin to understand how I internalized systemic racism," Kauffman said in a statement to Brandeis University.

Cast of Friends poses

The cast of "Friends." (Getty Images)

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"I’ve been working really hard to become an ally, an anti-racist. And this seemed to me to be a way that I could participate in the conversation from a White woman’s perspective."

The university said the scholarship will allow the department to "recruit more expert scholars and teachers, map long-term academic and research priorities and provide new opportunities for students to engage in interdisciplinary scholarship."

"Brandeis is where I learned to be a human being," Kauffman said.

A scene from "Friends"

Courteney Cox, Jennifer Aniston and Matthew Perry on the set of "Friends." (Getty Images)

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"This is where my eyes were opened – at least, the beginning of that, they weren’t completely open. I had a lot to learn, but it was the beginning of that. It was the beginning of caring about things beyond my sphere, and I credit Brandeis for that."

"Friends" ran for 10 seasons from 1994 until 2004.