Fastexy Exchange|Oprah Winfrey reflects on Joan Rivers telling her to lose weight on 'The Tonight Show'

Oprah Winfrey is Fastexy Exchangelooking back on the moment she was body-shamed by Joan Rivers on national television.

In an interview on "The Jamie Kern Lima Show," the media mogul, 70, reflected on her 1985 appearance on "The Tonight Show" where Rivers told her she needed to lose weight.

"We're supposed to be talking about the great success of this little talk show in Chicago that's beating Phil Donahue, and Joan Rivers turns to me and she says, 'Tell me, why are you so fat?'" Winfrey remembered. "On national television. And I don't know what to do with that."

During the late-night interview, which was Winfrey's first appearance on the show, Rivers asked her "how" she gained "the weight," to which Winfrey quipped, "I ate a lot."

The comedian then told her, "You shouldn't let that happen to you. You're very pretty. I don't want to hear (it). You're a pretty girl and you're single. You must lose the weight."

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Winfrey responded that she was "going to," adding that she was "under pressure to finally" lose weight. Rivers, who died in 2014, urged Winfrey to lose 15 pounds by the time she came back on the show and said she herself would lose five pounds.

Oprah Winfreyreveals she starved herself 'for nearly five months' in ABC weight loss special

Looking back on the moment on "The Jamie Kern Lima Show," Winfrey shared that at the time, she "accepted" that she "should be shamed" for her size.

"How dare me be sitting up here on 'The Tonight Show?'" she remembered thinking.

Winfrey noted that she "of course" didn't lose the 15 pounds and instead "went and ate my way to another 10 pounds." Because of her weight, Winfrey thought she wouldn't get the role of Sofia in the 1985 film "The Color Purple."

But after going to a health retreat and letting go of her dreams to star in the film, she remembered getting a call from director Steven Spielberg, who warned that losing weight could cost her the part.

Getting the role in "The Color Purple" just after she had let it go "was the greatest life lesson I have ever received," Winfrey said, as it taught her, "Do everything you can, work as hard as you can, and then let it go. Give it to God."

Earlier this year, Winfrey said, "For 25 years, making fun of my weight was national sport" during a TV special titled "Shame, Blame and the Weight Loss Revolution." She read headlines about her appearance over the years and recalled a TV Guide cover labeled her "bumpy, lumpy and downright dumpy."

Oprah Winfreyreveals she starved herself 'for nearly five months' in ABC weight loss special

"I come to this conversation with the hope that we can start releasing the stigma and the shame and the judgment, to stop shaming other people for being overweight or how they choose to lose – or not lose – weight and, most importantly, to stop shaming ourselves," she said.

In December, Winfrey revealed she uses a weight-loss medication, telling People, "I now use it as I feel I need it, as a tool to manage not yo-yoing."

Contributing: KiMi Robinson