To call Tuesday's taping of the two-part Surprise Oprah! A Farewell Spectacular at Chicago's United Center anything less than, well, spectacular, is certainly an understatement.
After all, it's not everyday you see so many celebs gather together to celebrate someone. Then again, not everyone is Oprah Winfrey.
So what did the stars who were on hand have to say about the big shindig?
"It was phenomenal," Aretha Franklin told E! News' very own Ben Lyons backstage. "I've never seen a presentation or a production quite like this one. But it was so deserving. Absolutely deserving."
"It was like the Jurassic Park of celebrities!" exclaimed Jamie Foxx, who, during the taping, sang "Isn't She Lovely?" while being accompanied by Stevie Wonder.
"I'm glad I came here because it's a fantastic atmosphere," Simon Cowell pointed out.
Meanwhile, Alicia Keys said she "felt blessed to be a part of this moment" and Usher called his participation in the event as career-defining.
Rosie O'Donnell, who will be taking over Oprah's studio when she launches her new show later this year on OWN, revealed that nobody in attendance had any idea who else was involved.
"It was such top secret news that until I arrived this morning and I saw the list, I was like, are you kidding me?" she said.
What's not so top secret, though, is how Oprah's program managed to endure for 25 years.
"I think it's her spirit," said Madonna. "I think it's the fact that she really is a compassionate human being. She's entertaining, but she wants to help people."
Surprise Oprah! A Farewell Spectacular airs May 23 and May 24, and the final episode of The Oprah Winfrey Show airs May 25.