During Robin Williams's legendary appearance on the show (January 29, 2001 – more on that later), he used the question as an opportunity to do what he did best: Riff.
"There's seating at the front," is his immediate answer. "The concert begins at five. It'll be Mozart, Elvis and one of your choosing."
But then he lapses into sincerity. "If heaven exists, to know that there's laughter, that would be a great thing." He gives the tiniest of pauses to set up the punchline: "Just to hear God go, 'Two Jews walk into a bar…'"
As Lipton reveals, Williams's installment of the series was the first-ever two-hour episode: The actor actually spoke and performed for the audience for over five hours, but Lipton and the producers simply couldn't bear to edit the performance any shorter than two hours, according to the DVD extras.
Lipton was unable to even ask his first question for the first nine minutes of Williams's appearance, and it took seven minutes for him to get to his follow-up.
Finally, the part of his appearance that's passed into legend: Lipton confirms on the DVD commentary that one member of the audience was actually taken away in an ambulance after the show, having developed a hernia from laughing so hard at Williams.
For more on Robin Williams's tragic death and his legacy of comic genius, pick up the latest issue of PEOPLE, on newsstands Friday
If you or someone you know is considering suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).
The Williams family is asking well-wishers to send contributions to charities close to the actor's heart in lieu of flowers. Suggested organizations include St. Jude Children's Research Hospital, Challenged Athletes, USO, the Muhammad Ali Parkinson Center, the Christopher and Dana Reeve Foundation and Glide Memorial Church in San Francisco.