Will Ferrell Cries About Kristen Stewart & Robert Pattinson Breakup on Conan O'Brien

Who knew Will Ferrell was such a Twi-hard?

OK! NEWS: WILL FERRELL, PAUL RUDD IN ANCHORMAN 2 TRAILER LEAK — FUNNY OR NOT?

The funnyman made a visit to Conan O'Brien last night to promote his new flick, The Campaign, and appeared suddenly distant mid-interview.

Conan asked what was wrong, noting he'd never seen the actor so down and out.

While Will was initially reluctant to talk about it, after some prodding he admitted it was the very public K-Stew and RPattz split that had him feeling deflated.

"She cheated on him!" he exclaimed to a befuddled Conan.

OK! NEWS: WILL FERRELL ANNOUNCES ANCHORMAN SEQUEL ON CONAN O'BRIEN

"What they had was so special, Conan!" Will said, fighting back tears. "They were in love and she just threw it all away! She's a trampire!"

Check it out below.