Tom – who famously jumped up and down on the couch on the 'Oprah Winfrey Show' while discussing his love for Katie Holmes – claimed the 57-year-old personality taught people how to "change" themselves.
He told the audience: "You have always had the power to change lives. And that is the lesson you brought."
Madonna revealed she admired Oprah because she was a "self made woman" who has shown people that hard work and determination pay off.
She said: "It's no secret that millions of people are inspired by 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 encouraging people to dream big to work hard, to read a book, to ask questions, to get an education no matter who you are or where you come from."
Maria – who recently split from 'Terminator' actor Arnold after it was revealed he had fathered a secret love child with a member of their household staff – came on stage with Oprah's friend Gayle King.
Speaking to the chat show host, Maria said: "You have given me love, support, wisdom and most of all truth."
Jamie Foxx serenaded Oprah with a version of 'Isn't She Lovely', before the song's original writer Stevie Wonder rose up from under the stage to perform a new track he had written specifically for her.
Beyonce Knowles also sang her new hit 'Run the World (Girls)', while Josh Groban and Patti LaBelle sang 'Over the Rainbow' from 'The Wizard of Oz'.
It was also announced at the end of the tapings that 25 new libraries are to be built across the US in Oprah’s honour, while Diane Sawyer added 25,000 oak trees will be planted in tribute to her.