Jake Gyllenhaal Doesn't Smile or Laugh in Russia -- It's Stupid (VIDEO)

The many premieres and press junkets for 'Prince of Persia' have taken Jake Gyllenhaal around the world, and taught him about cultural norms in the process.

As he explained on the 'Late Show' (weeknights, 11:35PM ET on CBS), he took advice from a Russian etiquette book a little too seriously -- leading to some disastrous interviews.

"On our way to Russia, they gave us an etiquette book," said Gyllenhaal. "It says, 'Don't laugh or smile, or they'll think you're stupid or crazy.' I swear to God that's what it says ... And so I started to get really nervous..."