VIDEO : Kanye West Gets Caught Smiling on Camera Hilariously Stops Immediately

For one brief moment, Kanye West was spotted laughing and enjoying himself, but he quickly turned his smile into a frown when he realized he was on camera. The rapper was back in his hometown, Chicago, watching the Bulls play the Cleveland Cavaliers, and in a Vine that's gone viral, he's seen chatting with former Bulls player Scottie Pippen, flashing a grin before putting on a straight face. During the game, Kanye also made his way on to the court to perform "All Day."??