Today Oprah revealed her "big secret": she has a half-sister she never knew about!

"Imagine my shock just a few months ago, at the end of October, when I found out I have another sister living just 90 minutes away," Winfrey, 56, said.

Winfrey's half-sister, single mother of two Patricia, had been given up for adoption in Milwaukee, Wis., by Winfrey's mother, Vernita Lee, in 1963.

"I was 9 years old at the time of [Patricia's adoption], living with my father in Nashville, Tenn.," Winfrey said. "I had no idea my mother was even pregnant."

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