With an audience of 13,000 very excited fans, Winfrey took the stage and took in the love. The show's producers created the "Surprise Spectacular" for her, and Winfrey had no idea what was going to happen.
Tom Hanks took the hosting reigns for the first "Surprise Spectacular" show, while Will and Jada Pinkett Smith helped out with the second.
Aretha Franklin sang "Amazing Grace." She also joined Usher for the show's finale song, "Oh Happy Day," as sparkly confetti filled the arena. Josh Groban and Patti LaBelle sang "Somewhere Over the Rainbow" as Winfrey sat in a white chair onstage. And Jamie Foxx and Stevie Wonder sang "Isn't She Lovely" to Winfrey.
Maria Shriver appeared on the same day it was revealed her husband, Arnold Schwarzenegger, fathered a child with a woman on his household staff more than a decade ago.
Other stars included Michael Jordan, Tom Cruise, Jerry Seinfeld, Madonna, Halle Berry, Queen Latifah, Katie Holmes, Dakota Fanning, Diane Sawyer and Beyonce.
Winfrey's celebrity guests weighed in backstage on the talk show queen's impact over the last 25 years.
"You won't see it again, simple as that. Twenty-five years, she went out at the top, she redefined this kind of TV. My opinion was she redefined television forever," said Simon Cowell.
Madonna said Winfrey was one of the few women that she could look up to and learn from.
"Whatever she does, she's a star, and I can't imagine she will ever stop pushing the envelope," she said.
"I'm just hoping that she knows how much love there is for her, not just in the entertainment industry but around the world," said LaBelle.
Winfrey knows that because, besides the U.S., "The Oprah Winfrey Show" airs in 150 different countries - at least it will for another week.
Winfrey announced in November 2009 that she would end "The Oprah Winfrey Show" this year after 25 years. Tuesday's taping will air May 23 and 24, before Winfrey's final show on May 25.
Fans happy to be a part of last shows
The 13,000 fans that got to attend the taping gave Winfrey a standing ovation when she first walked on the stage.
"I'm so inspired by her, her wisdom, her knowledge, her feel goodness. I'm just going to miss that in general," said Chellena Black.
It's hard to believe the show is almost done for good.
"She'll still be somewhere around. She'll always be with us," said Polly Stearns.
Longtime fan Victoria King showed off her Winfrey artwork that was painted right onto her head.
"We miss her already, you know? I'm a hairdresser, been a hairdresser for 30 years. I'm just dedicating my head to her," she said.
The show was full of surprises for Winfrey, and outside, there was another surprise - an Oprah lookalike.
"They tell me their problems because they don't quite get it," said Caroline Hodge. "They tell me how much Oprah inspires them."
The Associated Press contributed to this report.