Oprah Winfrey Oprah Winfrey

It's been 25 years, but Oprah finally has a favorite guest of all time.

It's not Tom Cruise — or even James Frey — but Dr. Tererai Trent, a woman from a poverty-stricken village in Zimbabwe who is determined to offer the children there the education she was barred from obtaining.  

"She's my favorite because she symbolizes everything I believe the Oprah show stands for," Winfrey said. "Her story encapsulates the essence of every lesson we've shared over the past 25 years: hope, your thoughts create your reality, gratitude, it doesn't matter where you come from, keep reaching for your dreams, and above all, you have the power."

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Oprah donated $1.5 million to Trent to make her dreams of building a school come true. "We're going to build a school together!" Oprah shouted. This is the second school Oprah will have helped build from the ground-up. Winfrey opened the Oprah Winfrey Leadership Academy for Girls in South Africa in 2007.

Oprah's final show airs May 25.