HBO has unveiled its most revealing trailer yet for Game of Thrones Season 3.

In what the network has billed as an "invitation to the set," executive producer D.B. Weiss - along with multiple cast members - preview the new episodes as being filled with "tremendous new characters" that "shake up the picture."

There are higher stakes and "loyalties are torn apart" during a "season of tremendous reversals of fortune,” as Weiss teases, telling viewers they will be “pleasantly surprised and horrified... in equal measure."

Perhaps coolest of all? We see Ciarán Hinds dressed as Wildling leader Mance Rayder for the first time. Check it out for yourself:

Game of Thrones Season 3 gets underway on March 31.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.