The Originals and The Vampire Diaries have already filmed their big crossover episode for The CW this season, but the guest stars might just be bigger than fans had expected.

Klaus Opts For 'Mass Murder' On 'The Originals'

It seems Nina Dobrev, who's recently had her work cut out for her playing both Elena and doppelganger Katherine on The Vampire Diaries, is headed to The Originals as Tatia.

"There was a character's name introduced a long time ago in [The Vampire Diaries] season three in associated with Klaus [Joseph Morgan] and Elijah [Daniel Gillies] and how they became vampires," explained The Originals creator Julie Plec in an interview with E! on Thursday.

Steven Krueger Marvels At 'The Originals' Premiere

Plec went on to explain that Tatia had been the original doppelganger, the one both Klaus and Elijah had been in love with. Apparently the series plans to explore the doomed Tatia, who will of course be played be The CW's queen of doppelganger: Dobrev.

Plec has often claimed that getting high-profile guest stars from The Vampire Diaries to make guest appearances would be difficult because of their busy shooting schedule, but it looks like the two shows managed to work something out.

"Nina Dobrev will be visiting The Originals for a nice little storyline in our fifth episode which airs November 3…" Plec told E! as she teased out the Tatia appearance.

"Esther, their mother, killed her [Tatia] so that she could make Klaus not a hybrid," continued Plec. "There's lots of secrets and scandal and romance and terrible tragedy attached to her character. We'll get to go back into the past and see how that all played out."

Tatia will likely come up to coincide with the return of Klaus' mother in New Orleans, who has come to cause trouble for her remaining family.

The Originals returns to The CW for a second season on a new night Monday, October 8 at 8 p.m. ET/PT.