Following the success of The Vampire Diaries, The CW decided to bring us the spin-off show The Originals, which is currently showing its first season. Julie Plec is the executive producer on The Originals and she has opened up about the bond between Hayley and Elijah and how Klaus will react to this.

The Originals cast
Plec explained to Collider, "Elijah, as you know, is a good protector and tends to be drawn to people, in spite of himself. When you have a situation like that, he cares deeply about that child that she’s carrying and maybe is starting to have his own level of concern that it’s more than just the child that he’s protecting and caring for. It’s definitely not a good thing, but it’s fun to watch."
She added "Whether you’ve watched The Vampire Diaries or not, even within this series, it’s very clear that Klaus is very territorial and that he likes what’s his to remain his. So, I have a feeling that will stir up a lot of conflicted emotions for him, as well. Rational or irrational, he never felt properly parented, loved or taken care of. When he starts to feel his family slipping away from him, or what he claims as his own finding their interests elsewhere, he tends to act out in ways that are not necessarily the most mature or appropriate. He will definitely have an opinion."

Daniel Gillies plays Elijah
The Originals stars Joseph Morgan, Daniel Gillies, Claire Holt, Phoebe Tonkin, Charles Michael Davis, Daniella Pineda, Leah Pipes and Danielle Campbell, and airs on The CW on Tuesday nights.
The Originals interview