Double Prediction by Nahuel Olivera

The magician shows an envelope (front and back) and says that there is a double prediction in there.
The magician mixes his poker deck (the viewer can also mix the deck), and asks the viewer to separate two cards from the deck. The magician puts these two cards next to the envelope.
Then the magician opens the envelope and two cards are inside, which surprisingly coincide with the viewer's selected cards!