It's taken three seasons but The Vampire Diaries and The Originals are finally intersecting thanks to the vampire shows' oldest friendship - Stefan (Paul Wesley) and Klaus (Joseph Morgan).

What is his reaction to seeing Klaus again for the first time in a while?

Wesley: "Holy s--t, we have so much history and so many experiences together, but we are so different now." He's also hiding a secret from Klaus when he first sees him, so it's not completely innocuous. [Stefan] is a little on edge because he's afraid that Klaus may figure out [that] secret. He kind of has to fool him into thinking he's there for a reason that he's not. That creates a little bit of awkwardness and unease in Stefan's mind, [but] I think he's relieved to see someone that was once his friend.

How is Klaus going to react to the fact that Caroline was pregnant and just had twins?

Wesley: They discuss it, for sure. Klaus keeps his cool.

The Vampire Diaries and The Originals crossover event kicks off Friday at 9/8c on The CW.