Oprah's final guest has been kept a secret until now. Turns out the 58-year-old talk show legend has NO guests booked for the final episode. Rather, Lady O will talk about lessons she's learned over the past 25 years. We know what you're thinking ... buzzkill.

Winfrey told the audience, "This is my love letter to you."

The final show, which airs tomorrow, also has Tyler Perry, Maria Shriver and Gayle King in the audience.

An audience member revealed to the Associated Press:

    "It was just her the whole time, a recap of what she believed in, what we've given her as viewers and what she hopes she has given us."

Find out what Madonna had to say about Oprah during one of the talk show's final episodes ... after the jump.