Conversation so far:
What celebrities has Oprah Winfrey interviewed?
Winfrey hosted a rare prime-time interview with Michael Jackson, which became the fourth most-watched event in American television history.
Who else has she interviewed?
Winfrey appeared on the Late Show with David Letterman.
When did she appear on the late show?
On December 1, 2005.

Question: Did she appear on his show more then once?
Self-contained rewrite: Did Oprah Winfrey `appear on the show more then once?