Letterman On 'Oprah's Next Chapter': 'I'm Sorry' (VIDEO)

For more than 20 years, Oprah Winfrey says, the public has believed that she and comedian David Letterman have been involved in a bitter feud. Since the rumor began, Letterman and Oprah addressed their dispute on his late-night talk show as well as on "The Oprah Winfrey Show." Now, during an episode of "Oprah’s Next Chapter," Oprah reveals a side of the story she says she's kept to herself for almost 25 years.

In the late 1980s, Oprah says she was a guest on the "Late Show with David Letterman" twice. Then, for many years after those appearances, Letterman made jokes about her not wanting to come back and started a fake campaign to be a guest on Oprah’s daytime talk show.

For a while, Letterman says he wanted his viewers to believe he and Oprah were involved in a feud. “It was great for me when we, when I, would bait you about coming on the show,” Letterman tells Oprah. “Big laughs.”

Letterman says he thought their so-called feud started after he called Oprah and asked her to be a guest on a show he was filming in Chicago. “I called you -- I'll never forget this -- so I got you on the phone, and you barked at me. You said, ‘Oh well, the least you could have done was call me on a hard line,’” he says. “So I thought, Oh no, I didn't even get beyond hello, and I've pissed her off.”

After Letterman extended the invitation to be a guest, he says Oprah replied, “I am totally out of town.”

Oprah, on the other hand, has a different memory -- one she never shared with Letterman until now. “You had asked me before to do [your show] in Chicago,” she says. “And it was a terrible experience for me. The guy in the audience started yelling, ‘Get her, Dave!’ You were sort of baiting the audience, and there were a bunch of drunk guys down the front. I was trying to like, you know, mitigate the whole thing, and it felt so uncomfortable to me. I didn't want to have that experience again. That's really all it was for me.”

After hearing her side of the story, Letterman apologizes to Oprah. “It never registered to me that that would be offensive nor do I remember the episode,” he says. "I'm more than embarrassed, and I bet if I had the courage to look at that videotape, it would sicken me. I'm sorry. I'm very sorry.”

"Oprah's Next Chapter" airs Sundays at 9 p.m. ET on OWN.