Oprah Winfrey has warned pal Lee Daniels to stop using the N-word, telling him that if he keeps it up they can't be friends.

Daniels, Winfrey and Forest Whitaker sat down with Parade magazine to discuss their upcoming film The Butler, which chronicles the Civil Rights movement through the eyes of White House butler Cecil Gaines (Whitaker), who served under seven presidents.

During the chat, Daniels said that he's used the word often in the past, but Oprah set him straight.

“It’s a word I used quite a bit," Daniels tells Parade, "until Oprah sat me down and talked to me about its power."

"You cannot be my friend and use that word around me," the TV mogul added. "It shows my age, but I feel strongly about it... I always think of the millions of people who heard that as their last word as they were hanging from a tree."

Daniels, who has since stopped using the word, claims he still experiences racism on a daily basis in New York City.

"It’s a given. I can’t even get a taxi. I send my [white] assistant out to get a taxi because I can’t," he says.

Whitaker, who "never did" use the term, says he's experienced plenty of racist moments in his life also.

"I’ve had many incidents in my life of racism. I’ve been thrown on the ground. I’ve been frisked. I’ve been arrested so many times I couldn’t tell you. I have no need to talk about it," he says.

"If you can’t accept that these things are going on, you’re living an illusion."

Winfrey added that people "need to see" the movie because the youth of today know "diddly-squat" about the civil rights movement.

The director is hoping for a PG-13 rating so more people can be exposed to the film's message. "Lee Daniels' The Butler" opens in theaters August 16.