Who Will Oprah Winfrey be Reunited With Tomorrow?

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Daytime TV queen Oprah Winfrey has everyone guessing what she will reveal to her audience on Monday's show, after she told Thursday's audience that she will have a personal on-air reunion.

Winfrey, who is in the middle of the final season of her ratings-shattering, 25-season-running show, wouldn't say with whom she will be reuniting, only revealing that it involves something she's learned about recently that is known to only a few people close to her.

"I thought I'd seen it all. But this, my friends, is the miracle of all miracles," she said in a promotion for Monday's broadcast.

"I was given some news that literally shook me to my core. This time, I'm the one being reunited," she said. "I was keeping a family secret for months, and on Monday you're going to hear it straight from me."

Harpo, Winfrey's production company, declined to provide further details on the nature of Monday's episode.

Winfrey has never been one to shy away from sharing the details of her tumultuous family history, which has involved sexual abuse by family members and the death of a son shortly after she gave birth to him as a teenager.

It has been speculated that Winfrey is using her Chicago-based show to reveal this unknown detail of her personal history in order to keep other media from getting hold of the story first.

Sensational celebrity biographer Kitty Kelley, who wrote a 2010 unauthorized biography of Winfrey, has said she believes the secret is a half-sister of Winfrey's that was placed for adoption as a baby, according to Time Out Chicago columnist Robert Feder.

Kelly also alleges in her Winfrey biography that Vernon Winfrey isn't Oprah's biological father. Kelley claims that she discovered the actual father's identity but is keeping mum until Winfrey learns the truth herself.

Large-scale and dramatic reunions have been a major theme on "The Oprah Winfrey Show" since its inception in 1986.

Winfrey famously reunited 100 members of the Osmonds, brought together both the screen family from "The Sound of Music" and descendants of the real-life members of the musical Von Trapp family, and reunited singer Seal on air with his foster sister.