Bonnie finally finds a worthy adversary in Klaus’ right-hand witch, Greta.

You already know the May 5 episode of The Vampire Diaries is going to be mind-blowing, but it sounds like even the most savvy of fans won’t see the many twists coming. ”It’s pretty much just going to be surprise after surprise the whole way through,” Lisa Tucker, who plays Klaus’ witch Greta, tells HollywoodLife.com. And we’re finally going to see Luka’s long-lost sister show off those powers we’ve heard so much about.

Executive Producer Julie Plec recently told reporters that Kat Graham would be at her “most bad-ass fierce” on tomorrow night’s episode, which meant only one thing in my mind: a witch-on-witch smackdown! And while Lisa won’t totally give up the goods, she does admit: ”We have a confrontation. … And it’s very intense.”

And considering what Lisa told me the last time we spoke (“Greta is not someone you want to mess with,” etc.) you can bet Bonnie’s in for a legit fight.

I also couldn’t resist asking Lisa what it’s like working with the phenomenal Joseph Morgan – and as you might expect, she tells me he isn’t nearly as terrifying as his “original” vampire persona.

“He’s the sweetest guy ever, but he plays such a jerk,” Lisa says — although I think “jerk” might be a bit of an understatement here. “Joseph is fantastic. And his accident his fantastic. He’s just so focused, and you can see that even when the cameras are down, he’s still in character. It’s great to see how dedicated he is, because Klaus is such a vital part of the end of the season.”

Check out an extended preview of tomorrow night’s episode, “The Sun Also Rises”, below:

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