VIDEO: Zach Galifianakis Gets Sean Penn 'Between Two Ferns'

Sean Penn must be a big fan of The Hangover, otherwise we're not sure why he agreed to appear on Zach Galifianakis's Funny or Die Web show, Between Two Ferns.

OK! VIDEO: SCHMUCKS STEVE & ZACH FIGHT BETWEEN TO PLANTS

Zach decided to put on a special act for his sit-down interview with Sean.

Appearing as his twin brother Seth, the comedian does his best to make his interview with the actor as uncomfortable as possible.

OK! NEWS: INTRODUCING OK!'S ONLINE BOOK CLUB — IT'S KIND OF A FUNNY STORY

Check out the interview below! Warning: Language NSFW.

Join OK!'s Online Book Club on Tuesday at 8 p.m. to read the book of Zach's upcoming movie, It's Kind of a Funny Story!