As much as we have thoroughly enjoyed Peter Pan (Robbie Kay) terrorizing our favorite Storybrooke residents for the first half of Once Upon a Time’s third season, we are giddy at the prospect of a new big bad. According to E! News, Lost alum Rebecca Mader is going to play an iconic villainess set wreak havoc on the quaint little town in the back half of the season.

The news site says Rebecca’s character will be around for multiple episodes when the series returns from hiatus on March 9, 2014, but we don’t know exactly who she’s set to portray. We’re being teased that her character will be a “major character, with a major arc, and it’s a meaty role.” All we know is we can’t wait to see some epic scenes with the Evil Queen (Lana Parrilla) and Rumple (Robert Carlyle) and this new villainess.

“Thrilled to welcome @bexmader to the #OnceUponATime family as... Well you'll just have to wait and see!” co-creator Adam Horowitz teased. And as for the lucky lady that landed the part, she’s over the moon as well. “I couldn't be more excited and thrilled to be joining the cast of #OUAT Christmas came early this year!” Rebecca gushed.

And while the identity of Rebecca’s on-screen character is being kept under lock and key, we do know when we will get a first glimpse at the big bad. Make sure to catch the mid-season finale on December 15 because that’s when the jaw-dropping reveal will happen, in a promo for the second half of the season. Count us in!

Who do you think Rebecca will be playing on Once? Hit the comments and let the speculation begin!

Once Upon a Time airs Sunday nights at 8 p.m. ET on ABC.

Source: E! News

Carson Blackwelder is an Assistant Editor at Wetpaint Entertainment. Follow him on Twitter and Google+!