The illusionist was giving a live demonstration of the death-defying stunt he begins on Monday. He will suspend himself upside down on a thin wire 50 foot above New York's Central Park for three days.
Using electro-magnetic boots, David will walk on and under the wire high above an ice rink owned by the billionaire businessman.
"This is by far the most difficult thing I've ever done. I thought being in a block of ice for 63 hours was, but that was nothing compared to this," he said, referring to a stunt he carried out in 2000.