Smiling, even if faking it, is an art form. And it’s even more difficult for a celebrity because they have to continually pose for the camera. Some don’t do it, whether because it’s tiring or because they’d like to strike a more “cool” pose.

Kanye West is the latest to join the trend started by Victoria Beckham. But what’s behind their frozen expressions? You can find out in the gallery. Click on “expand gallery” and then on “show text” to read the information.