Gossip Girl’s Sebastian Stan will finally make his long-awaited debut as Alice in Wonderland’s Mad Hatter on this Sunday’s episode of Once Upon a Time. And we’ve got an exclusive sneak peek!
While we’ll learn how the Mad Hatter became, well, mad in Wonderland, his real-world counterpart, Jefferson, is just as eccentric. Surprisingly, his kidnapping and drugging of Emma (Jennifer Morrison) is the least of his offenses.
Watch the clip HERE!