Oprah Winfrey revealed to the world that she has a secret sister she didn't know existed until November.
Audience members gasped as Oprah revealed the details of the bombshell family drama.
Patricia and Oprah share the same mother, Vernita Lee, but have different fathers. The 48-year-old from Milwaukee was given up for adoption just days after she was born.
"I had no idea that my mother had given up a baby in 1963, I was 9 years old at the time, living with my father in Nashville, and didn't even know my mother was pregnant," Oprah explained.
Patricia says she tried for years to learn the identity of her birth mother, to no avail.
"She had made the decision at that particular time that she did not want to see me," explained Patricia.
But Patricia obtained her adoption documents and with the help of her two children she used clues in them to pursue the truth.
Patricia says she actually made the shocking discovery that Oprah was her sister in 2007, and tried every way possible to contact the TV titan.
"She had tried, and tried, and tried again, even wrote an e-mail to our offices back in 2007. She never once thought to go to the press, she never once thought to sell the story…so thank you, thank you," said Oprah, holding her sister's hand.
Patricia eventually made inroads with the family by finding her long-lost niece. Word spread through the family and Oprah finally found out about her secret sister in November.
"Finally I said to my assistant Libby, 'What is going on in this family? What is going on?' She says, 'You have a sister,' and I'm like, 'Whaaat?!' "Oprah told the audience.
She shared home video of their first face-to-face get-together at a family Thanksgiving gathering.
Oprah says she was immediately struck by Patricia's eerie resemblance to her other half-sister, who died in 2003, also named Patricia.
"It was so uncanny to us and to everybody in this family how much this Patricia looked like, moved like, talked like Pat," she said.
Oprah and Patricia sat down together and confronted their mother about the family secret.
"I thought it was a terrible thing for me to do, that I had done, gave up my daughter," Vernita Lee told them.
"We see this very often with adoptions, that one party wants to open and the other does not, and again a lot of it has to do with shame from the past and fear," Mardie Caldwell, founder and CEO of Lifetime Adoption Center, told INSIDE EDITION.
Oprah says she and Patricia are now getting to know each other and are still processing the shocking revelation.
"What has been the most rewarding part of this for you?" Oprah asked Patricia.
"Finding my family," she said.