'Oprah's Next Chapter': 5 of the show's biggest revelations [Video]

The upcoming "Oprah's Next Chapter" interview with Lance Armstrong is the most talked-about TV moment of the year so far. In fact, it's probably one of the biggest cultural stories of the year, period, as embattled cyclist Armstrong sits down with Oprah to clear the air about his doping scandal.

[Related: After years of denial, why is Lance Armstrong admitting he used PEDs now?]

How big? Oprah's already decided to expand the episode, set to air Thursday night on OWN, to two episodes totaling two and a half hours, saying she didn't feel she could edit it down further than that. And the mogul appeared on BFF Gayle King's show, "CBS This Morning," to address rumors about the interview's contents, and discuss the extensive secrecy precautions her team and Armstrong's took to keep leaks at bay. (Oprah specifically mentioned hiring a different driver to take her to the airport, and personally carrying the tapes with her on the plane "along with my dog food and dog leashes back to Harpo.")

[Related: Olympics could drop cycling over Lance Armstrong revelations]

But what should we really expect from this one-on-one? Oprah's not afraid to get confrontational -- her face-off with disgraced fabulist James Frey in 2006 is a talk-show skirmish for the ages. But she's since said she regrets her harshness with Frey, and King wondered on "CBS This Morning" if Oprah had landed Armstrong because of a perception that she wouldn't push him. "There was a lot of talk that you were chosen because you would not go deep, you would not go hard," King said. Can Oprah really get Armstrong to open up, or is this an Al-Capone's-vault-style bust waiting to happen?

[Related: Lance Armstrong's doping admission: Questions Oprah should have asked]

Oprah's already claimed that "the most important questions and the answers that people around the world have been waiting to hear were answered" -- and past episodes of "Oprah's Next Chapter" have proved that she can still get the goods from the celebrities she spotlights. We've collected five of the biggest revelations from Oprah's OWN interviews -- tears, feuds, denial, and forgiveness. We can't predict whether the Armstrong "chapter" will make the list, but we know it's possible.

Rihanna forgives Chris Brown

Frequently dabbing at her eyes, pop star Rihanna took Oprah through her feelings after the infamous "incident" in which then-boyfriend Chris Brown assaulted her in early 2009 -- and Oprah frequently seemed flummoxed as Rihanna said things like, "We love each other and we probably always will," and described her feelings of protectiveness towards Brown in the aftermath. "He made that mistake because he needed help, and who's gonna help him?" Rihanna wondered plaintively. "I was more concerned about him." (Oprah, somewhat at a loss: "That is really powerful.")

But Rihanna's ability to forgive Brown -- by repairing her relationship with her father, who'd been an abusive husband but a solid dad -- is what made headlines, despite the fact that the singer's other comments still seemed more than tinged with co-dependency. (As of this writing, the pair are collaborating, and perhaps back together as a couple, but the status changes daily.)

Kelsey Grammer: Cocaine "was fun"

The episode featuring the former "Frasier" star is full of good stuff, not least the revelation that his marriage to third wife Camille was over as soon as it started (as Oprah noted, he couldn't even call her by name, referring to her as "this person"), and that he'd agreed to her "Real Housewives" stint because "she'd always wanted to be famous."

Grammer also talks at length about his sister's murder in 1975, and how he might be able forgive the men involved if only they would tell the truth about what they did.

But for our money, the biggest bombshell is Grammer admitting that cocaine wasn't all bad. Calling his relationship with the drug "a love affair," he said, "It was fun, and I was fun. It just eventually becomes something you can't keep doing." Refreshing candor, and not what you usually hear from stars in recovery.

Letterman, Oprah end feud

Late-night veteran David Letterman sat down with Oprah (wearing white socks) earlier this month to talk about his heart surgery, their feud, and the infidelities that nearly ended his marriage to Regina Lasko. Letterman took full responsibility for the scandal, but said it's been a boon to his marriage and his self-esteem: "I feel better about myself; my relationship with my wife is SIC never better."

The host's notorious self-loathing surfaced several times (he still "can't forgive that behavior" on his own part), in particular when Oprah asked what went through his mind as he prepared to come out onstage and do his show during that time. Saying that it shows "the breadth and width of what a weasel I can be," Letterman admitted that he was thinking, "'Maybe I can get a little sympathy out of this deal.'" Ouch.

But our favorite bit is when Oprah shone a light on their long-running "feud." Letterman didn't think it was real, so much, although "it was great for" his show when he leveraged it as a joke. But Oprah said she'd gone on his show once, long ago, and "it was a terrible experience" for her, specifically getting heckled by a bunch of drunk guys. Letterman didn't remember that at all and promptly apologized -- and they laid the vendetta to rest with a handshake.

Lady Gaga "kind of liked" the smell of the meat dress

Much of this first-season ep was devoted to the mutual admiration society Oprah and Lady Gaga formed for each other as two super-famous role models with non-profit foundations -- and it's kind of fun to see how touched Gaga was by Oprah's "sense of sisterhood and mothering towards" her.

Gaga also refused to talk about her current man (or if it even was a man) in any detail, which Oprah admitted was her fault: "I told you yesterday you should never talk about your relationships." Oprah did get Gaga to say that she wants lots of kids -- a "soccer team"'s worth.

But let's get to the meat of it, by which we mean the meat dress Gaga wore to the 2012 MTV Video Music Awards. (The dress has its own Wikipedia page, by the way.) Did it smell by the end? "Oh yes," Gaga laughed, "but I kind of liked it." Why? "I don't like talking to celebrities," and the stench kept most people at a safe distance. We'll have to try that…

Whitney Houston's brother "loved" Bobby Brown

Oprah headed to Atlanta last March to talk with Whitney Houston's daughter, Bobbi Kristina; her brother, Gary; and her sister-in-law, manager, and confidante Patricia about all the stories swirling around the singer's untimely death. Why did Bobby Brown get kicked out of the memorial? Did Patricia think Whitney had started using again?

Patricia denied that Whitney had any substance issues in the last part of her life, though "the handwriting was on the wall" as far as the damage drugs may have already done to the star. Patricia also went through some impressive vagueness contortions in an effort to call Whitney's then-gentleman-friend Ray Jay shady, without using his name or the word "shady." "I was afraid for other things, lifestyle," she said, and "I saw her chasing a dream, you know, looking for love in all the wrong places."

Neither the drug denials nor the idea that Ray Jay was a subpar influence is a huge surprise, but Gary's comments about Whitney's explosive ex, Bobby Brown, might be. Gary categorically denied that the family didn't want him at the memorial service: "He was supposed to be there."

Gary also said, "I loved Bobby; Bobby was a good guy." The jury's out on that one (at best); Gary conceded that "I don't know how good they were for one another," but said he couldn't exert much influence, then busted out one of the best metaphors for a toxic relationship we've ever heard. "It's like scissors," he said. "You get in between that, you're gonna get cut." Maybe not the best taste in brothers-in-law, but Gary has a way with words.

If we missed a big moment, let us know in the comments -- and tell us whether you think Oprah can get Lance to confess for real.

The first half of "Oprah's Next Chapter" featuring Lance Armstrong airs Thursday, 1/17 at 9 PM on OWN.