Conversation so far:
How many celebrities did Oprah have on her show
Winfrey interviewed a plethora of public figures and everyday people during the show's 25-year history.
Did the celebrities do anything special for Oprah's show
Winfrey sat down in a prime-time special broadcast with Michael Jackson. Jackson, an intensely private entertainer, had not given an interview in 14 years

Question: When was Michael on her show
Self-contained rewrite: When was Michael Jackson on Oprah's show