Watch Will Ferrell Cry About Kristen Stewart Cheating on Robert Pattinson

Leave it to Will Ferrell to come up with a term like "trampire."

Ferrell showed up on "Conan" last night to promote his upcoming movie "The Campaign," but it quickly became clear in the interview that something was bothering Ferrell. When Conan O'Brien asked him about it more, Ferrell burst into a tear-filled rant about how Kristen Stewart cheated on Robert Pattinson, and how it was getting him down.

This sort of thing isn't new for Ferrell's "Conan" appearances. On other occasions where Ferrell has dropped in on "Conan" or on "The Tonight Show" while O'Brien was still hosting, Ferrell has done everything from shaving Conan's beard to showing up as Ron Burgundy.

Ferrell seems to be pretty well updated on the situation, which has become rich with details after various bits of rumor and evidence have appeared: the news first broke over a week ago that Stewart cheated, followed later by pics of the affair. Then, reports that Pattinson had evicted Stewart from his house and shacked up with Reese Witherspoon emerged.

Ferrell concludes his tearful tirade by calling Stewart a "trampire," which one can only hope will now become a regular part of the English vocabulary. Hey, it beats some of the reactions from other Twihards.

Watch the video below: