Maria Shriver, Tom Hanks, Will Smith and Jada Pinkett Smith among the celebrities who appeared during the four-hour taping Tuesday.
More than 20,000 people packed Chicago's United Center to watch the celebrity-packed live taping of Oprah Winfrey's second and third final shows.
Before the show even started, a man proposed to his girlfriend on-stage -- who accepted as the audience cheered on. Among those in the audience: Oprah BFF Gayle King, former Chicago mayor Richard Daly, the Food Network's Tyler Florence and NFL's Emmitt Smith.
Tom Hanks hosted the first hour.
"Now Oprah, I know you do not like surprises. Let me see if I can put you at ease. There was an English playwright who said there's no surprise more magical than the surprise of being loved, and that is what tonight is all about... pulling off this little show at the United Center has been the best kept secrets," he said.
The first guest was Tom Cruise (who did not jump on any couches). Joked Winfrey: "You looked like you were 10 when you on my show in 1988. And what was up with my hair?" She says he's been on the show 12 times.
Next, America's Got Talent's Jackie Evancho sings from the Wizard of Oz, when she is joined by Josh Groban to sing "Somewhere Over the Rainbow." They were joined by Patti LaBelle, who brought down the house with the audience cheering and clapping as Oprah kept bringing her hands to her face. LaBelle kicked off her shoes into the audience midsong.
"We're just 10 minutes into the show!" Oprah enthused.
Next Madonna took the stage. "You look surprised," she said. "Yeah, kinda!" said Oprah.
"It's no secret that millions of people are inspired by Oprah. I am one of them." Madonna said she only has one living role model: Oprah. "She's a self-made woman who's been at the top of her game for over 25 years and she is still kicking ass. And she is still kicking ass!"
Between each celeb guest or performance, a video broadcast on three giant screens in the United Center, where the Chicago Bulls normally play. Videos ranged from Oprah's most memorable moments ("You get a car!") to embarrassing bloopers (awkwardly dancing with MC Hammer) to skits with celebs like Tina Fey and Steve Carell.
Dakota Fanning came out next to introduce "Oprah Babies," aka viewers who had been watching their entire lives. They revealed how Oprah had changed their lives. One young girl said she was able to survive abuse because of Oprah; Oprah spent a few minutes speaking to her off the microphone right after their segment ended.
Next, Beyonce showed up in a tuxedo leotard and sang "Run the World (Girls)" with a stage full of backup dancers. Mouthed Oprah from the audience, where she was sitting with Cruise, "Oh my God!" Beyonce's performance was taped twice, and the audience stood up and cheered each time.
Next, Hanks announced that the audience had brought some of their "favorite things" -- books that they planned to donate to a school library in New Orleans. John Legend appeared live via satellite to accept them.
Diane Sawyer then walked out as a giant lit-up tree rose to the ceiling of the United Center. Sawyer announced that 25,000 oak trees would be planted in Oprah's honor. Joked Oprah: "I just gave everybody a tree! you get a tree and you get a tree and you get a tree. Everybody gets a tree!"
Then, Halle Berry, Katie Homes and Queen Latifah walked out. "We love you, Oprah," said Berry, who then recalled how Oprah viewers have changed the world by becoming foster parents and starting charitable foundations. Holmes and Latifah also called out audience members by name, many of whom got a hug from Winfrey.
Rascal Flatts closed the show by singing "I Won't Let You Go," as Oprah listened and swayed from the audience.
The first hour wrapped up with all the stars returning to stage and Oprah hugging them one by one.
"I feel the love!" said Oprah, who had mascara running down her cheeks. "And I thank you for it. Thank you for being a part of this great night, this celebration for what you have done for the Oprah Winfrey Show. ... your being here tonight.... honors me in the deepest way possible."
Before the second show started, a producer joked that John Travolta was locked in the bathroom. (Travolta famously appeared on the 25th season premiere to give away the trip to Australia.)
Will Smith and Jada Pinkett Smith hosted the second hour. The first guest was Michael Jordan, who revealed that he came to Chicago the same year as Oprah: 1984. "MJ in the house!" said Oprah.
Jamie Foxx then began singing -- and was soon joined by Stevie Wonder, who rose from the floor playing his piano. He changed several lyrics to include Oprah; the audience jumped to their feet.
"I'm a little nervous right now," admitted Wonder before revealing that he had written a song especially for Oprah. Oprah waved the cameras away from getting too close so she could lean on his piano and enjoy the song. She gave him a big hug, whispered in his ear and said, "Hey baby," once it was done.
Next, Jerry Seinfeld came to the stage and delivered a comedy routine: "We are trying to figure out. How much can one person take? We are going to keep going until you say we can't take it anymore!"
Simon Cowell was up next and began to talk about The Oprah Winfrey Show's impact on music before stumbling over his words, saying "blah blah blah" and starting again. Oprah blew him a kiss from the audience. "I can also say firsthand that you are a very good kisser," joked Cowell.
Rosie O'Donnell came out next, flanked by dancers. She sang "Fever" but changed the lyrics about how much she'll miss Oprah. "You saved me from depression when you gave us Dr. Phil!" was one verse, before Dr. Phil showed up on stage. Also joining him: Oprah proteges Nate Berkus and Dr. Oz. (O'Donnell's OWN show will tape at Chicago's Harpo Productions.)
Maria Shriver then made her long-rumored appearance on stage -- the day after her husband, Arnold Schwarzenegger, announce that he'd fathered a child out of wedlock with a former household employee. Oprah kept her arm tightly wrapped around Shriver's shoulders. Also joining them on stage: King.
"Well Oprah, for more than 30 years, you bestowed the most amazing friendship on me, given me love, support, wisdom and most of all truth," said Shriver, who worked with Winfrey and King at the same TV station in Baltimore in the beginning of their television careers. Tyler Perry also appeared and urged the audience, "I know it's getting late but wake up in here, wake up, show the love!"
Kristin Chenoweth sang next as the lights were dimmed and people filled the stage holding single lights. "You're trying to break me down. That did it. You're looking for a breakdown. That was it right there," said Oprah. "All right, carry me on out of here! Oh my God, there's still more! This is newsworthy."
Next up was Oprah's mentor Maya Angelou, who performed a poem she had written especially for Oprah as Alicia Keys played the piano. Oprah appeared emotional as she sat directly across from Maya. Keys then sang "Super Woman."
Oprah left the stage next, and was overheard complaining about how much her shoes hurt as the audience laughed.
Her longtime boyfriend Stedman Graham then took the stage, and Oprah grabbed King's arm in surprise. "Honey, you are so special, and I am so happy... I'm so proud of you," he said as the audience made a collective "aww" at the rare public appearance by Graham.
"I cannot believe a colored girl from the back woods of Mississippi has done all you have done with your show, your magazine, your film company, radio, and your also hands on with your school in South Africa," he said to applause, "while launching a network!"
Graham -- who also announced he loved her and called her "sweetheart" -- then introduced Aretha Franklin, who appeared in good health as she performed a bluesy version of "Amazing Grace." Oprah raised her arms up from the audience, as Graham made a rare public display of affection by putting his arm around Oprah's waist.
Oprah finally broke into her infamous "ugly cry" after the music sped up and Franklin began dancing around. "Enough! Aretha Franklin and Michael Jordan in the same night? What is that? I can't take it anymore," she said on stage after, half laughing and half crying as she danced with Franklin.
Hanks appeared again after. "There's been a lot of highlights tonight," he said. "Morehouse college, Maya Angelou, Stedman!"
"Holy Jesus from God, what is happening? Stedman is on stage!" joked Oprah.
Then a producer came out and asked Oprah to speak louder, and Will Smith quipped, "Don't tell Oprah what to do! That's Oprah! You're fired."
Oprah then took a minute to thank her fans: "I've never experienced anything like this and I say once again thank you for taking me to a place that's beyond joyous. I'm going to have to process it and look at it on tape to see what actually happened here. It feels like the rapture, so thank you all for that!"
Smith announced there's one last surprise, as a full symphony began to back Usher, who sang "O.M.G." mashed with "Oh Happy Day" as Hanks awkwardly danced.
Confetti shot up from the audience, and the stars rejoined Oprah on stage as she thanked everyone.
Four hours later, the show was over. And within 30 minutes, the chairs had been broken down and the confetti was being swept up.
The shows will air in a two-part series on May 23 and May 24. Her final show airs May 25.