'Vampire Diaries' Casts Stefan's Ex: 5 Theories On Why She's Coming To Town

Forget vampires, witches, werewolves and hybrids, the next season of "The Vampire Diaries" is clearly shaping up to be all about ex-girlfriends.

"Pretty Little Liars" star Claire Holt has just been cast as Rebecca (otherwise known as Bex), a girl from Stefan's ravenous ripper days, who will make her mark on Mystic Falls, reports Zap2It. The details surrounding Bex's arrival to town are still a little fuzzy, but considering this is "TVD," we've got a feeling it's got little to do with reminiscing about the good evil times she spent with Stefan (Paul Wesley) and more about stirring up some trouble. So, what really brings Bex to town? It's time to play the "TVD" guessing game! (You know, the one where we share our five wildest theories that are inevitably never right because the writers are always 10 steps ahead? That one.). Check out why we think Stefan's old flame is coming to Mystic Falls and share your best guesses after the jump.

1. An Alliance With Klaus: Klaus (Joseph Morgan) doesn't have many friends (R.I.P. Greta), but he's got his share of alliances. Perhaps Bex wants in on the hybrid clique?

2. She's A Blood-Digger!: Interesting that Bex was totally M.I.A. during Stefan's squeaky clean years, but now that he's running around town binging on human blood with Klaus (with a lot to go around, no doubt) she pops back up again. Now I ain't sayin' she a blood digger...

3. She's After Damon: Since Stefan always gets the girl, we wouldn't mind seeing Bex come to town only to declare that it was Damon (Ian Somerhalder) she had her eyes on all these years. It's only fair, right?

4. To Make Elena Miserable: It may not be Bex's main motivation for coming to Mystic Falls, but we're pretty sure it's on the agenda. To think poor Elena (Nina Dobrev) probably thought she had gone through enough ex-drama to last a lifetime with Katherine! Maybe she and Bonnie (Kat Graham), who will literally have some ghosts of girlfriends past to deal with, can plan some sleepovers to vent out their frustrations?

5. To Save Stefan: Okay, so maybe we're being too hard on the girl. For all we know, Bex is coming back to save her long-lost love from falling in with bad company. Perhaps we should give her the benefit of the doubt? Ha, who are we kidding? Even we can't take this theory seriously.

Why do you think Stefan's ex-girlfriend is coming to Mystic Falls?