Google a picture of Diego Klattenhoff today, and you'll likely get mugs of the handsome, mature actor viewers know from "Homeland" and "The Blacklist." Delve a little deeper and you'll find Klattenhoff in a different part of cultural lore. Klattenhoff memorably played Shane Oman in the cult hit "Mean Girls," aka the dude Regina George dumped Aaron Samuels for.