Reese Witherspoon says she “didn’t understand what homosexuality was” until she moved to Los Angeles.

While speaking with Regina King for Variety’s “Actors on Actors,” Witherspoon, 44, opened up about her experience on “Little Fires Everywhere,” detailing how a conversation she had with her grandmother as a child inspired a scene in the series.

The actress began, “That great experience of being able to look at a time that was actually 30 years ago and think: ‘I was a teenager then. What did my mom say about sexuality, race, class? What were the things that I was told that maybe were true or not true? How was I insensitive?'”

“No one spoke to me about sexuality when I was a teenager,” Witherspoon continued. “I didn’t understand what homosexuality was. My grandparents didn’t explain it. My parents didn’t explain it. I had to learn from somebody I met on an audition in Los Angeles.”

In “Little Fires Everywhere,” Witherspoon plays Elena Richardson, a mother who struggles to accept that her daughter, Izzy, is gay, a plot point that was only alluded to in the book the series is based on.

Witherspoon, who also served as an EP on the Hulu drama, told King she drew from a discussion about sexuality she shared with her grandmother back in the ’90s.

“We incorporated some of the conversation I had with my grandmother afterward. She said: ‘Homosexuality is very rare, Reese. That’s not a thing that happens very often,'” Witherspoon explained. “And we put it in the script. (My character) Elena says it because that’s what was said to me in Nashville, Tennessee, in 1994.”