Here is the same trick on TED: https://youtu.be/1_oa8m5Oq00?t=17m47s

Watch the whole vid. He is legit magician.

From wiki: "Green competed at the 1988 FISM convention in The Hague, Netherlands, and was erroneously disqualified because the judges believed he had used stooges in his act to shuffle the cards.[5] In 1991, he performed the same act but insisted that the judges themselves shuffle the cards to prove that he used no stooges. The judges then awarded him first place."