"Have you ever thought that, given the popularity you have — we haven’t broken the glass ceiling yet for women — that you could actually run for president and actually be elected?" he asked.
Winfrey paused before answering, as the audience laughed.
"I never considered the question, even a possibility,” she began, then suggested the question made her reconsider the idea.
"I just thought, 'Oh — oh?'" she continued.
"Because, it’s clear you don’t need government experience to be elected president of the United States," Rubenstein added.
"That’s what I thought," Winfrey said. "I thought, 'Oh gee, I don’t have the experience, I don’t know enough.' ... And now I’m thinking, 'Oh.'"
In January, Winfrey said during an appearance on "The Late Show with Stephen Colbert" that she would never run for president. 
“Is there any other charismatic African-American woman that both sides of the political aisle really love?” Colbert asked after a reference to former first lady Michelle Obama, prompting applause from the show's audience.
“Never,” Winfrey said. “No, no, it’s not my thing.”